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    Author / Editor / Organization Title Year Journal / Proceedings / Book
    A. I. Dzergach, V. S. Kabanov, A. M. Sessler & J. S. Wurtele About the Realization of Laser Acceleration Schemes based on Plasmoids in RF Wells 1998 (MOP46C)  
    BibTeX:
    @conference{Dzergach:MOP46C,
      author = {A. I. Dzergach, and V. S. Kabanov, and A. M. Sessler, and J. S. Wurtele},
      title = {About the Realization of Laser Acceleration Schemes based on Plasmoids in RF Wells},
      year = {1998},
      number = {MOP46C},
      note = {Contributed to European Particle Accelerator Conference (EPAC 98), Stockholm, Sweden, 22-26 Jun 1998}
    }
    					
    A.E. Charman, R.R. Lindberg, J.S. Wurtele & L. Friedland Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator: A Theoretical Study 2005 (TPAE066)  
    Abstract: A modified version of the Plasma Beat-Wave Accelerator scheme is presented, which is based on autoresonant phase-locking of the nonlinear Langmuir wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. Compared to traditional approaches, the autoresonant scheme achieves larger accelerating electric fields for given laser intensity; the plasma wave excitation is more robust to variations in plasma density; it is largely insensitive to the details of the slow chirp rate; and the quality and uniformity of the resulting plasma wave for accelerator applications may be superior.
    BibTeX:
    @conference{Charman:TPAE066,
      author = {A.E. Charman, and R.R. Lindberg, and J.S. Wurtele, and L. Friedland},
      title = {Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator: A Theoretical Study},
      year = {2005},
      number = {TPAE066},
      note = {Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee}
    }
    					
    J. Alsner, G. Andresen, A. Angelopoulos, D. Barna, N. Bassler, A. Belov, W. Bertsche, G.-J. Beyer, G.Bonomi, J. Borbely, I. Boscolo, S. B�ottner, P. Bowe, N. Brambilla, J. Bremer, R. Brusa, E. Butler, V. M. Byakov, L. Cabaret, C. Canali, C. Carraro, F. Castelli, C. Cesar, S. Chapman, M. Charlton, S. Cialdi, D. Comparat, G. Consolati, M. Corradini, F. Curreli, L. Dassa, A. Dax, J. DeMarco, N. Djurelov, H. D�lrath, M. Doser, G. Drobychev, A. Dudarev, A. Dupasquier, T. Eisel, Y. Enomoto, D. Fabris, B. Fahimian, J. Fajans, S. Federmann, R. Ferragut, G. Ferrari, A. Fisher, P. Folegati, A. Fontana, L. Formaro, S. Friedreich, M. Fujiwara, G. Gabrielse, A. Gervasini, M. George, M. Giammarchi, D. Gill, S. N. Gninenko, G. Gribakin, D. Grzonka, D. Hajdukovic, J. Hangst, W. Hardy, O. Hartley, F. Haug, R. Hayano, M. Hayden, R. Herrmann, E. Hessels, R. Heyne, H. Higaki, S. Hogan, M. Holzscheiter, M. Hori, D. Horv�ath, A. Humphries, C. Hunniford, R. Hydomako, H. Imao, K. Iwamoto, O. J�akle, L. Joergensen, B. Juhasz, F. Kaiser, Y. Kanai, I. Kantemiris, J. Kavanagh, A. Kellerbauer, R. Keyes, K. Kira, H. Knudsen, T. Kobayashi, D. Kolbe, A. Koglbauer, W. Kolthammer, S. Kovacevic, D. Krasnicky, H.-P. E. Kristiansen, L. Kurchaninov, N. Kuroda, V. Lagomarsino, R. Lambo, P. Larochelle, M. Leali, F. Leveraro, E. L. Rizzini, M. Lunardon, M. Lund, N. Madsen, G. Manuzio, S. Mariazzi, V. Mascagna, O. Massiczek, Y. Matsuda, V. A. Matveev, W. McBride, R. McConnell, R. McCullough, F. Merkt, K. Michishio, R. Miralbell, S. M�ller, A. M. andS. Moretto, C. Morhard, A. M�uller, Y. Nagata, G. Nebbia, P. Nedelec, T. Ninikowski, P. Nolan, M. Oberthaler, W. Oelert, K. Olchanski, A. Olin, J. Overgaard, D. Perini, S. Pesente, J. Petersen, V. Petracek, W. Pirkl, A. Povilus, M. Prevedelli, P. Pusa, F. Quasso, I. Al-Qaradawi, O. Ratib, C. Riccardi, P. Richerme, F. Robicheaux, O. Rohne, A. Rotondi, H. Saitoh, H. S. E. Sarid, G. Schettino, M. Scheid, T. Sefzick, S. Sellner, D. Sillou, D. Silveira, P. Somkuti, A. S�ot�er, M. Spacek, A. Speck, S. Stapnes, R. Steinborn, S. V. Stepanov, J. Storey, C. Storry, H. Stroke, S. Tegami, G. Testera, R. Thompson, D. Timson, G. Tino, K. Todoroki, K. T�ok�esi, H. Torii, D. Trezzi, A. V. Turbabin, A. V. Turbabin, U. Uggerh�j, K. Umlaub, R. Vaccarone, A. Vairo, V. Varentsov, L. Venturelli, G. Viesti, F. Villa, S. Vranjes, H.R.J.Walters, J. Walz, U. Warring, M. Weel, C. Welsch, D. van der Werf, E. Widmann, B. Wouters, J. Wrubel, J. Wurtele, Y. Yamazaki, Z. Yoshida, P. Zal�an, S. Zavatarelli, A. Zenoni, M. Zielinski, N. Zurlo & D. Zvezhinskij ELENA: An Upgrade to the Antiproton Decelerator at CERN 2011 International Journal of Modern Physics A
    Vol. 26, pp. 390-395  
    Abstract: CERN has a long tradition of pursuing fundamental physics on a variety of energy scales. For anti-protons CERN famously produced the high-energy SPS beam but also the world's only and unique sources of low-energy anti-protons ? first the Low Energy Anti-proton Ring (LEAR) and thereafter the Anti-proton Decelerator (AD).

    The scientific demand for low-energy anti-protons at the AD continues to grow. More rapid progress and much higher measurement precision might be possible by upgrading the AD to increase and optimize the number of cold anti-protons that can be trapped and accumulated. To achieve this the construction of an Extra Low ENergy Antiproton (ELENA) ring is proposed which involves both the addition of a small storage ring and electrostatic beam lines to the experiments. The design parameters have been carefully studied and agreed upon over several years. At least during the next decade there is no alternative low-energy anti-proton source for physics to be done now.

    BibTeX:
    @article{,
      author = {J. Alsner and G.B. Andresen and A. Angelopoulos and D. Barna and N. Bassler and A.S. Belov and W. Bertsche and G.-J. Beyer and G.Bonomi and J.S. Borbely and I. Boscolo and S. B�ottner and P.D. Bowe and N. Brambilla and J. Bremer and R.S. Brusa and E. Butler and V. M. Byakov and L. Cabaret and C. Canali and C. Carraro and F. Castelli and C.L. Cesar and S. Chapman and M. Charlton and S. Cialdi and D. Comparat and G. Consolati and M. Corradini and F. Curreli and L. Dassa and A. Dax and J. DeMarco and N. Djurelov and H. D�lrath and M. Doser and G. Drobychev and A. Dudarev and A. Dupasquier and T. Eisel and Y. Enomoto and D. Fabris and B. Fahimian and J. Fajans and S. Federmann and R. Ferragut and G. Ferrari and A. Fisher and P. Folegati and A. Fontana and L. Formaro and S. Friedreich and M.C. Fujiwara and G. Gabrielse and A. Gervasini and M.C. George and M. Giammarchi and D.R. Gill and S. N. Gninenko and G. Gribakin and D. Grzonka and D. Hajdukovic and J.S. Hangst and W.N. Hardy and O. Hartley and F. Haug and R.S. Hayano and M.E. Hayden and R. Herrmann and E.A. Hessels and R. Heyne and H. Higaki and S.D. Hogan and M. Holzscheiter and M. Hori and D. Horv�ath and A.J. Humphries and C.A. Hunniford and R. Hydomako and H. Imao and K. Iwamoto and O. J�akle and L.V. Joergensen and B. Juhasz and F.J. Kaiser and Y. Kanai and I. Kantemiris and J. Kavanagh and A. Kellerbauer and R. Keyes and K. Kira and H. Knudsen and T. Kobayashi and D. Kolbe and A. Koglbauer and W.S. Kolthammer and S. Kovacevic and D. Krasnicky and H-P E. Kristiansen and L. Kurchaninov and N. Kuroda and V. Lagomarsino and R. Lambo and P. Larochelle and M. Leali and F. Leveraro and E. Lodi Rizzini and M. Lunardon and M. Lund and N. Madsen and G. Manuzio and S. Mariazzi and V. Mascagna and O. Massiczek and Y. Matsuda and V. A. Matveev and W. McBride and R. McConnell and R.W. McCullough and F. Merkt and K. Michishio and R. Miralbell and S.P. M�ller and A. Mohri andS. Moretto and C. Morhard and A. M�uller and Y. Nagata and G. Nebbia and P. Nedelec and T. Ninikowski and P. Nolan and M. Oberthaler and W. Oelert and K. Olchanski and A. Olin and J. Overgaard and D. Perini and S. Pesente and J. Petersen and V. Petracek and W. Pirkl and A. Povilus and M. Prevedelli and P. Pusa and F. Quasso and I.Y. Al-Qaradawi and O. Ratib and C. Riccardi and P. Richerme and F. Robicheaux and O. Rohne and A. Rotondi and H. Saitoh and H. Sandaker E. Sarid and G. Schettino and M. Scheid and T. Sefzick and S. Sellner and D. Sillou and D.M. Silveira and P. Somkuti and A. S�ot�er and M. Spacek and A. Speck and S. Stapnes and R. Steinborn and S. V. Stepanov and J.W. Storey and C.H. Storry and H.H. Stroke and S. Tegami and G. Testera and R.I. Thompson and D. Timson and G. Tino and K. Todoroki and K. T�ok�esi and H.A. Torii and D. Trezzi and A. V. Turbabin and A. V. Turbabin and U. Uggerh�j and K. Umlaub and R. Vaccarone and A. Vairo and V.L. Varentsov and L. Venturelli and G. Viesti and F. Villa and S. Vranjes and H.R.J.Walters and J. Walz and U. Warring and M. Weel and C. Welsch and D.P. van der Werf and E. Widmann and B. Wouters and J. Wrubel and J.S. Wurtele and Y. Yamazaki and Z. Yoshida and P. Zal�an and S. Zavatarelli and A. Zenoni and M. Zielinski and N. Zurlo and and D.S. Zvezhinskij},
      title = {ELENA: An Upgrade to the Antiproton Decelerator at CERN},
      journal = {International Journal of Modern Physics A},
      year = {2011},
      volume = {26},
      pages = {390-395},
      url = {http://www.worldscinet.com/ijmpa/26/2603n04/S0217751X11051718.html},
      doi = {http://dx.doi.org/10.1142/S0217751X11051718}
    }
    					
    G. Andresen, W. Bertsche, A. Boston, P. D. Bowe, C. L. Cesar, S. Chapman, M. Charlton, M. Chartier, A. Deutsch, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, K. Gomberoff, J. S. Hangst, R. S. Hayano, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. Povilus, F. Robicheaux, E. Sarid, D. M. Silveira, J. W. Storey, H. H. Telle, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Y. A. Collaboration Antimatter Plasmas in a Multipole Trap for Antihydrogen 2007 Phys. Rev. Lett.
    Vol. 98 (2), pp. 023402  
    Abstract: We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage lifetimes of antiproton and positron plasmas in the combined Penning-neutral trap, and compared these to lifetimes without the neutral trap fields. The magnetic well depth was 0.6 T, deep enough to trap ground state antihydrogen atoms of up to about 0.4 K in temperature. We have demonstrated that both particle species can be stored for times long enough to permit antihydrogen production and trapping studies.
    BibTeX:
    @article{andresen:023402,
      author = {G. Andresen and W. Bertsche and A. Boston and P. D. Bowe and C. L. Cesar and S. Chapman and M. Charlton and M. Chartier and A. Deutsch and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and K. Gomberoff and J. S. Hangst and R. S. Hayano and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. Povilus and F. Robicheaux and E. Sarid and D. M. Silveira and J. W. Storey and H. H. Telle and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki ALPHA Collaboration},
      title = {Antimatter Plasmas in a Multipole Trap for Antihydrogen},
      journal = {Phys. Rev. Lett.},
      publisher = {APS},
      year = {2007},
      volume = {98},
      number = {2},
      pages = {023402},
      url = {http://link.aps.org/abstract/PRL/v98/e023402},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.98.023402}
    }
    					
    G. Andresen, W. Bertsche, P. Bowe, C. Bray, E. Butler, C. Cesar, S. Chapman, M. Charlton, J. Fajans, M. Fujiwara, D. Gill, J. Hangst, W. Hardy, R. Hayano, M. Hayden, A. Humphries, R. Hydomako, L. J�rgensen, S. Kerrigan, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. Silveira, J. Storey, R. Thompson, D. van der Werf, J. Wurtele & Y. Yamazaki Antihydrogen formation dynamics in a multipolar neutral anti-atom trap 2010 Physics Letters B
    Vol. 685 (2-3), pp. 141 - 145  
    Abstract: Antihydrogen production in a neutral atom trap formed by an octupole-based magnetic field minimum is demonstrated using field-ionization of weakly bound anti-atoms. Using our unique annihilation imaging detector, we correlate antihydrogen detection by imaging and by field-ionization for the first time. We further establish how field-ionization causes radial redistribution of the antiprotons during antihydrogen formation and use this effect for the first simultaneous measurements of strongly and weakly bound antihydrogen atoms. Distinguishing between these provides critical information needed in the process of optimizing for trappable antihydrogen. These observations are of crucial importance to the ultimate goal of performing CPT tests involving antihydrogen, which likely depends upon trapping the anti-atom.
    BibTeX:
    @article{Andresen2010,
      author = {G.B. Andresen and W. Bertsche and P.D. Bowe and C. Bray and E. Butler and C.L. Cesar and S. Chapman and M. Charlton and J. Fajans and M.C. Fujiwara and D.R. Gill and J.S. Hangst and W.N. Hardy and R.S. Hayano and M.E. Hayden and A.J. Humphries and R. Hydomako and L.V. J�rgensen and S.J. Kerrigan and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D.M. Silveira and J.W. Storey and R.I. Thompson and D.P. van der Werf and J.S. Wurtele and Y. Yamazaki},
      title = {Antihydrogen formation dynamics in a multipolar neutral anti-atom trap},
      journal = {Physics Letters B},
      year = {2010},
      volume = {685},
      number = {2-3},
      pages = {141 - 145},
      url = {http://www.sciencedirect.com/science/article/B6TVN-4Y8PY5V-1/2/a4bf62a70fcd93284ec84909a53a2417},
      doi = {DOI: 10.1016/j.physletb.2010.01.066}
    }
    					
    G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, A. Deller, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins, S. Jonsell, L. V. Jorgensen, L. Kurchaninov, N. Madsen, S. Menary, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. e. Nasr, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Trapped antihydrogen 2010 Nature
    Vol. 468 (7324), pp. 673-676  
    Abstract: Antimatter was first predicted1 in 1931, by Dirac. Work with high-energy antiparticles is now commonplace, and anti-electrons are used regularly in the medical technique of positron emission tomography scanning. Antihydrogen, the bound state of an antiproton and a positron, has been produced2, 3 at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature?s fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom (about two parts in 1014 for the frequency of the 1s-to-2s transition4), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter5. However, so far experiments have produced antihydrogen that is not confined, precluding detailed study of its structure. Here we demonstrate trapping of antihydrogen atoms. From the interaction of about 107 antiprotons and 7?�?108 positrons, we observed 38 annihilation events consistent with the controlled release of trapped antihydrogen from our magnetic trap; the measured background is 1.4?�?1.4 events. This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen.
    BibTeX:
    @article{Andresen2010a,
      author = {Andresen, G. B. and Ashkezari, M. D. and Baquero-Ruiz, M. and Bertsche, W. and Bowe, P. D. and Butler, E. and Cesar, C. L. and Chapman, S. and Charlton, M. and Deller, A. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M. C. and Gill, D. R. and Gutierrez, A. and Hangst, J. S. and Hardy, W. N. and Hayden, M. E. and Humphries, A. J. and Hydomako, R. and Jenkins, M. J. and Jonsell, S. and Jorgensen, L. V. and Kurchaninov, L. and Madsen, N. and Menary, S. and Nolan, P. and Olchanski, K. and Olin, A. and Povilus, A. and Pusa, P. and Robicheaux, F. and Sarid, E. and Nasr, S. Seif el and Silveira, D. M. and So, C. and Storey, J. W. and Thompson, R. I. and van der Werf, D. P. and Wurtele, J. S. and Yamazaki, Y.},
      title = {Trapped antihydrogen},
      journal = {Nature},
      publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
      year = {2010},
      volume = {468},
      number = {7324},
      pages = {673--676},
      url = {http://dx.doi.org/10.1038/nature09610},
      doi = {http://dx.doi.org/10.1038/nature09610}
    }
    					
    G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. Humphries, R. Hydomako, S. Jonsell, L. Kurchaninov, R. Lambo, N. Madsen, S. Menary, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, D. Wilding, J. S. Wurtele & Y. Yamazaki Evaporative Cooling of Antiprotons to Cryogenic Temperatures 2010 Phys. Rev. Lett.
    Vol. 105 (1), pp. 013003  
    Abstract: We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.
    BibTeX:
    @article{PhysRevLett.105.013003,
      author = {Andresen, G. B. and Ashkezari, M. D. and Baquero-Ruiz, M. and Bertsche, W. and Bowe, P. D. and Butler, E. and Cesar, C. L. and Chapman, S. and Charlton, M. and Fajans, J. and Friesen, T. and Fujiwara, M. C. and Gill, D. R. and Hangst, J. S. and Hardy, W. N. and Hayano, R. S. and Hayden, M. E. and Humphries, A. and Hydomako, R. and Jonsell, S. and Kurchaninov, L. and Lambo, R. and Madsen, N. and Menary, S. and Nolan, P. and Olchanski, K. and Olin, A. and Povilus, A. and Pusa, P. and Robicheaux, F. and Sarid, E. and Silveira, D. M. and So, C. and Storey, J. W. and Thompson, R. I. and van der Werf, D. P. and Wilding, D. and Wurtele, J. S. and Yamazaki, Y.},
      title = {Evaporative Cooling of Antiprotons to Cryogenic Temperatures},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {2010},
      volume = {105},
      number = {1},
      pages = {013003},
      url = {http://prl.aps.org/abstract/PRL/v105/i1/e013003},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.105.013003}
    }
    					
    G. B. Andresen, W. Bertsche, A. Boston, P. D. Bowe, C. L. Cesar, S. Chapman, M. Charlton, M. Chartier, A. Deutsch, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, K. Gomberoff, J. S. Hangst, R. S. Hayano, R. Hydomako, M. J. Jenkins, L. V. Jorgensen, L. Kurchaninov, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. D. Page, A. Povilus, F. Robicheaux, E. Sarid, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Production of antihydrogen at reduced magnetic field for anti-atom trapping 2008 Journal of Physics B: Atomic, Molecular and Optical Physics
    Vol. 41 (1), pp. 011001 (5pp)  
    Abstract: We have demonstrated production of antihydrogen in a 1 T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3 T) and ATRAP (5 T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the Antihydrogen Laser PHysics Apparatus (ALPHA) device, which can capture and cool antiprotons at 3 T, and then mix the antiprotons with positrons at 1 T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.
    BibTeX:
    @article{0953-4075-41-1-011001,
      author = {G B Andresen and W Bertsche and A Boston and P D Bowe and C L Cesar and S Chapman and M Charlton and M Chartier and A Deutsch and J Fajans and M C Fujiwara and R Funakoshi and D R Gill and K Gomberoff and J S Hangst and R S Hayano and R Hydomako and M J Jenkins and L V Jorgensen and L Kurchaninov and N Madsen and P Nolan and K Olchanski and A Olin and R D Page and A Povilus and F Robicheaux and E Sarid and D M Silveira and J W Storey and R I Thompson and D P van der Werf and J S Wurtele and Y Yamazaki},
      title = {Production of antihydrogen at reduced magnetic field for anti-atom trapping},
      journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
      year = {2008},
      volume = {41},
      number = {1},
      pages = {011001 (5pp)},
      url = {http://stacks.iop.org/0953-4075/41/011001}
    }
    					
    G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. D. Page, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Y. Kanai & Y. Yamazaki (Hrsg.) First Attempts at Antihydrogen Trapping in ALPHA 2008 Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics
    Vol. 1037 (1), pp. 241-248  
    Abstract: The ALPHA apparatus is designed to produce and trap antihydrogen atoms. The device comprises a multifunction Penning trap and a superconducting, neutral atom trap having a minimum-B configuration. The atom trap features an octupole magnet for transverse confinement and solenoidal mirror coils for longitudinal confinement. The magnetic trap employs a fast shutdown system to maximize the probability of detecting the annihilation of released antihydrogen. In this article we describe the first attempts to observe antihydrogen trapping.
    BibTeX:
    @conference{andresen:241,
      author = {G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and R. D. Page and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki},
      title = {First Attempts at Antihydrogen Trapping in ALPHA},
      journal = {Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics},
      publisher = {AIP},
      year = {2008},
      volume = {1037},
      number = {1},
      pages = {241-248},
      url = {http://link.aip.org/link/?APC/1037/241/1},
      doi = {http://dx.doi.org/10.1063/1.2977843}
    }
    					
    G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. D. Page, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Y. Kanai & Y. Yamazaki (Hrsg.) Antiproton compression and radial measurements 2008 Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics
    Vol. 1037 (1), pp. 96-105  
    Abstract: Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile, and its relation to that of the electron plasma. We also measure the outer radial profile by ejecting antiprotons to the trap wall using an octupole magnet.
    BibTeX:
    @conference{andresen:96,
      author = {G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and R. D. Page and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki},
      title = {Antiproton compression and radial measurements},
      journal = {Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics},
      publisher = {AIP},
      year = {2008},
      volume = {1037},
      number = {1},
      pages = {96-105},
      url = {http://link.aip.org/link/?APC/1037/96/1},
      doi = {http://dx.doi.org/10.1063/1.2977860}
    }
    					
    G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. D. Page, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki A novel antiproton radial diagnostic based on octupole induced ballistic loss 2008 Phys. of Plasma
    Vol. 15 (3), pp. 032107  
    Abstract: We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning--Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.
    BibTeX:
    @article{andresen:032107,
      author = {G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and R. D. Page and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki},
      title = {A novel antiproton radial diagnostic based on octupole induced ballistic loss},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2008},
      volume = {15},
      number = {3},
      pages = {032107},
      url = {http://link.aip.org/link/?PHP/15/032107/1},
      doi = {http://dx.doi.org/10.1063/1.2899305}
    }
    					
    G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Y. A. Collaboration Compression of Antiproton Clouds for Antihydrogen Trapping 2008 Phys. Rev. Lett.
    Vol. 100 (20), pp. 203401  
    Abstract: Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.
    BibTeX:
    @article{andresen:203401,
      author = {G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki ALPHA Collaboration},
      title = {Compression of Antiproton Clouds for Antihydrogen Trapping},
      journal = {Phys. Rev. Lett.},
      publisher = {APS},
      year = {2008},
      volume = {100},
      number = {20},
      pages = {203401},
      url = {http://link.aps.org/abstract/PRL/v100/e203401},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.100.203401}
    }
    					
    G. B. Andresen, W. Bertsche, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, D. R. Gill, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, L. V. Jorgensen, S. J. Kerrigan, J. Keller, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Y. A. Collaboration Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning-Malmberg trap used for antihydrogen trapping 2009 Physics of Plasmas
    Vol. 16 (10), pp. 100702  
    Abstract: In many antihydrogen trapping schemes, antiprotons held in a short-well Penning?Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency r of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30% in some cases) can be lost to a hitherto unidentified bounce-resonant process when r is close to zero.
    BibTeX:
    @article{Andresen2009,
      author = {G. B. Andresen and W. Bertsche and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and D. R. Gill and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and L. V. Jorgensen and S. J. Kerrigan and J. Keller and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki ALPHA Collaboration},
      title = {Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning--Malmberg trap used for antihydrogen trapping},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2009},
      volume = {16},
      number = {10},
      pages = {100702},
      url = {http://link.aip.org/link/?PHP/16/100702/1},
      doi = {http://dx.doi.org/10.1063/1.3258840}
    }
    					
    C. M. Ankenbrandt Status of Muon Collider Research and Development and Future Plans 1999 Phys. Rev. ST Accel. Beams
    Vol. 2, pp. 081001  
    Abstract: The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from a heavy-Z target and proceeding through the phase rotation and decay (π → μ νμ) channel, muon cooling, acceleration, storage in a collider ring and the collider detector. We also present theoretical and experimental R & D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the R & D since the Feasibility Study of Muon Colliders presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A. Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].
    BibTeX:
    @article{ankenbrandt-1999-2,
      author = {Charles M. Ankenbrandt},
      title = {Status of Muon Collider Research and Development and Future Plans},
      journal = {Phys. Rev. ST Accel. Beams},
      year = {1999},
      volume = {2},
      pages = {081001},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:physics/9901022}
    }
    					
    M. Babzien, I. Ben-Zvi, P. Catravas, J.-M. Fang, T. C. Marshall, X. J. Wang, J. S. Wurtele, V. Yakimenko & L. H. Yu First observation of self-amplified spontaneous emission at 1.064 $[$mu$]$m 1998 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 407 (1-3), pp. 267-270  
    Abstract: We report evidence of self-amplified spontaneous emission at 1064†nm. Single pass, on-axis microwiggler emissions into a 25†nm bandwidth have been recorded as a function of beam charge, and show a clear enhancement over spontaneous emission after threshold. These are the first measurements of SASE at such a short wavelength, and employ the smallest period wiggler used to date in a successful SASE experiment. The experiment has been performed with the MIT microwiggler at the Accelerator Test Facility at BNL. A single micropulse at 34†MeV with a variable charge of 0-1†nC and <5†ps bunch length is passed through the microwiggler and emissions into a limited solid angle and bandwidth, selected by an aperture and interference filter, are focused onto a silicon photodiode. Enhancement of the emissions from 2 to 6 times the spontaneous emission level is observed at the highest charges.
    BibTeX:
    @article{Babzien:1998jx,
      author = {Babzien, M. and Ben-Zvi, I. and Catravas, P. and Fang, J-M. and Marshall, T. C. and Wang, X. J. and Wurtele, J. S. and Yakimenko, V. and Yu, L. H.},
      title = {First observation of self-amplified spontaneous emission at 1.064 $[$mu$]$m},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1998},
      volume = {407},
      number = {1-3},
      pages = {267--270},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3VHNRSY-1X/1/567cbfd88482f8a38e078ef479d370b3}
    }
    					
    M. Babzien, I. Ben-Zvi, P. Catravas, J.-M. Fang, T. C. Marshall, X. J. Wang, J. S. Wurtele, V. Yakimenko & L. H. Yu Observation of self-amplified spontaneous emission in the near-infrared and visible wavelengths 1998 Phys. Rev. E
    Vol. 57 (5), pp. 6093-6100  
    Abstract: We report evidence of self-amplified spontaneous emission (SASE) at 1064 and 633 nm. To our knowledge, these are the first measurements of SASE at such a short wavelength and employ the smallest period wiggler, 8.8 mm, used to date in a successful SASE experiment. The experiments were performed with the MIT microwiggler at the Accelerator Test Facility at BNL. Single-pass, on-axis microwiggler emissions within a 25 nm bandwidth have been recorded as a function of beam charge and show a clear enhancement over spontaneous emission. For the measurement at 1064 nm, a single micropulse at 34 MeV with a variable charge of 0--1 nC and less than 5 ps full width at half maximum bunch length was passed through the microwiggler and emissions into a limited solid angle and bandwidth, selected by an aperture and interference filter, were focused onto a silicon photodiode. Enhancement of the emissions, from 2 to 6 times the spontaneous emission level, was observed at the highest charges. In addition, we observed SASE gain at a wavelength of 633 nm at a beam energy of 48 MeV, without detailed measurements.
    BibTeX:
    @article{PhysRevE.57.6093,
      author = {Babzien, M. and Ben-Zvi, I. and Catravas, P. and Fang, J.-M. and Marshall, T. C. and Wang, X. J. and Wurtele, J. S. and Yakimenko, V. and Yu, L. H.},
      title = {Observation of self-amplified spontaneous emission in the near-infrared and visible wavelengths},
      journal = {Phys. Rev. E},
      publisher = {American Physical Society},
      year = {1998},
      volume = {57},
      number = {5},
      pages = {6093--6100},
      doi = {http://dx.doi.org/10.1103/PhysRevE.57.6093}
    }
    					
    E. Y. Backhaus Collisionless Relaxation in Beam-Plasma Systems 2001 School: University of California at Berkeley  
    BibTeX:
    @phdthesis{Backhaus,
      author = {Backhaus, E. Yu.},
      title = {Collisionless Relaxation in Beam-Plasma Systems},
      school = {University of California at Berkeley},
      year = {2001}
    }
    					
    E. Y. Backhaus & J. S. Wurtele Coupled moment expansion model for the dynamics in a beam-plasma system 2000 Phys. of Plasma
    Vol. 7 (11), pp. 4729-4747  
    Abstract: A new technique is developed to study beam dynamics in an overdense plasma. This technique is an alternative to, and extension of, the well-known envelope equation formalism, and it can be used in systems with nonlinear forces. It is based on a systematic moment expansion of the Vlasov equation. In contrast to the envelope equation, which is derived assuming constant rms beam emittance, this coupled moment expansion (CME) model allows the emittance to vary through coupling to higher order moments. The CME model is implemented in slab geometry in the absence of return currents. The evolution of the low order moments of the distribution function are followed with ~100 ordinary differential equations. The CME simulation yields rms beam sizes,velocity spreads, and emittances that are in good agreement with particle-in-cell simulations for a wide range of system parameters. New analytical results for the second-order moments in the phase-mixed state are obtained. Unlike previous results, these connect the final values of the second-order moments with the initial beam mismatch. These analytical estimates are in good agreement with the CME model and particle-in-cell simulations.
    BibTeX:
    @article{backhaus:4729,
      author = {E. Yu. Backhaus and J. S. Wurtele},
      title = {Coupled moment expansion model for the dynamics in a beam--plasma system},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2000},
      volume = {7},
      number = {11},
      pages = {4729-4747},
      url = {http://link.aip.org/link/?PHP/7/4729/1},
      doi = {http://dx.doi.org/10.1063/1.1314624}
    }
    					
    B. Barletta, S. Chattopadhyay, P. Chen, D. Cline, W. Craddock, W. Gabella, I. Hsu, T. Katsouleas, P. Kwok, P. Lai, W. Leemans, R. Liou, D. Meyerhofer, K. Nakajima, H. Nakanishi, C. Ng, Y. Nishida, J. Norem, A. Ogata, S. Rajagopalan, J. Rosenzweig, A. Sessler, J. Spencer, J. Su, G. Westenskow, D. Whittum, R. Williams & J. S. Wurtele Plasma-lens experiments at the Final Focus Test Beam 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 4, pp. 2638-2640  
    Abstract: We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5×1010, tunneling ionization of a gas target by an electron beam-an effect which has never been observed before-should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders
    BibTeX:
    @article{309412,
      author = {Barletta, B. and Chattopadhyay, S. and Chen, P. and Cline, D. and Craddock, W. and Gabella, W. and Hsu, I. and Katsouleas, T. and Kwok, P. and Lai, P. and Leemans, W. and Liou, R. and Meyerhofer, D.D. and Nakajima, K. and Nakanishi, H. and Ng, C.K. and Nishida, Y. and Norem, J. and Ogata, A. and Rajagopalan, S. and Rosenzweig, J. and Sessler, A. and Spencer, J. and Su, J.J. and Westenskow, G. and Whittum, D. and Williams, R. and Wurtele, J. S.},
      title = {Plasma-lens experiments at the Final Focus Test Beam},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {4},
      pages = {2638-2640},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309412}
    }
    					
    W. Barletta, S. Chattopadhyay, P. Chen, D. Cline, W. Craddock, W. Gabella, I. Hsu, R. Iverson, T. Katsouleas, P. Kwok, P. Lai, W. Leemans, R. Liou, D. D. Meyerhofer, K. Nakajima, H. Nakanishi, C. K. Ng, Y. Nishida, J. Norem, A. Ogata, S. Rajagopalan, T. Shintake, J. Rosenzweig, M. Ross, A. Sessler, J. Spencer, J. J. Su, N. Walker, G. Westenskow, D. Whittum, R. Williams & J. S. Wurtele P. Schoessow (Hrsg.) Plasma lens experiments at the final focus test beam 1995 The sixth advanced accelerator concepts workshop
    Vol. 335 (1), pp. 606-611  
    Abstract: We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam induced tunneling ionization of a working gas---the latter which has never been observed before. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.
    BibTeX:
    @conference{barletta:606,
      author = {W. Barletta and S. Chattopadhyay and P. Chen and D. Cline and W. Craddock and W. Gabella and I. Hsu and R. Iverson and T. Katsouleas and P. Kwok and P. Lai and W. Leemans and R. Liou and D. D. Meyerhofer and K. Nakajima and H. Nakanishi and C. K. Ng and Y. Nishida and J. Norem and A. Ogata and S. Rajagopalan and T. Shintake and J. Rosenzweig and M. Ross and A. Sessler and J. Spencer and J. J. Su and N. Walker and G. Westenskow and D. Whittum and R. Williams and J. S. Wurtele},
      title = {Plasma lens experiments at the final focus test beam},
      journal = {The sixth advanced accelerator concepts workshop},
      publisher = {AIP},
      year = {1995},
      volume = {335},
      number = {1},
      pages = {606-611},
      url = {http://link.aip.org/link/?APC/335/606/1},
      doi = {http://dx.doi.org/10.1063/1.48298}
    }
    					
    J. J. Barnard, J. Armijo, D. S. Bailey, A. Friedman, F. M. Bieniosek, E. Henestroza, I. Kaganovich, P. T. Leung, B. G. Logan, M. M. Marinak, R. M. More, S. F. Ng, G. E. Penn, L. J. Perkins, S. Veitzer, J. S. Wurtele, S. S. Yu & A. B. Zylstra Ion beam heated target simulations for warm dense matter physics and inertial fusion energy 2009 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 606 (1-2), pp. 134 - 138  
    Abstract: Hydrodynamic simulations have been carried out using the multi-physics radiation hydrodynamics code HYDRA and the simplified one-dimensional hydrodynamics code DISH. We simulate possible targets for a near-term experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCX-II) for studies of warm dense matter and inertial fusion energy-related beam-target coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include single-pulse planar metallic solid and foam foils. Concepts for double-pulsed and ramped-energy pulses on cryogenic targets and foams have been simulated for exploring direct drive beam-target coupling, and concepts and simulations for collapsing cylindrical and spherical bubbles to enhance temperature and pressure for warm dense matter studies.
    BibTeX:
    @article{Barnard2009134,
      author = {J. J. Barnard and J. Armijo and D. S. Bailey and A. Friedman and F. M. Bieniosek and E. Henestroza and I. Kaganovich and P. T. Leung and B. G. Logan and M. M. Marinak and R. M. More and S. F. Ng and G. E. Penn and L. J. Perkins and S. Veitzer and J. S. Wurtele and S. S. Yu and A. B. Zylstra},
      title = {Ion beam heated target simulations for warm dense matter physics and inertial fusion energy},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {2009},
      volume = {606},
      number = {1-2},
      pages = {134 - 138},
      note = {Heavy Ion Inertial Fusion - Proceedings of the 17th International Symposium on Heavy Ion Inertial Fusion},
      url = {http://www.sciencedirect.com/science/article/B6TJM-4W0R0GP-8/2/ef9c48af6ff38c4c64687b0d6a70fc69},
      doi = {DOI: 10.1016/j.nima.2009.03.221}
    }
    					
    J. J. Barnard, J. Armijo, R. M. More, A. Friedman, I. Kaganovich, B. G. Logan, M. M. Marinak, G. E. Penn, A. B. Sefkow, P. Santhanam, P. Stoltz, S. Veitzer & J. S. Wurtele Theory and simulation of warm dense matter targets 2007 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 577 (1-2), pp. 275 - 283  
    Abstract: We present simulations and analysis of the heating of warm dense matter (WDM) foils by ion beams with energy less than 1 MeV per nucleon to target temperatures of order 1 eV. Simulations were carried out using the multi-physics radiation hydrodynamics code HYDRA and comparisons are made to an analytical model and the code DPC. We simulate possible targets to be used in a proposed experiment at Lawrence Berkeley National Laboratory (the so-called Neutralized Drift Compression Experiment, NDCX II) for studies of WDM. We compare the dynamics of ideally heated targets under several assumed equations of state and explore target dynamics in the two-phase (fluid-vapor) regime.
    BibTeX:
    @article{Barnard2007275,
      author = {J. J. Barnard and J. Armijo and R. M. More and A. Friedman and I. Kaganovich and B. G. Logan and M. M. Marinak and G. E. Penn and A. B. Sefkow and P. Santhanam and P. Stoltz and S. Veitzer and J. S. Wurtele},
      title = {Theory and simulation of warm dense matter targets},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {2007},
      volume = {577},
      number = {1-2},
      pages = {275 - 283},
      note = {Proceedings of the 16th International Symposium on Heavy Ion Inertial Fusion - HIF 06},
      url = {http://www.sciencedirect.com/science/article/B6TJM-4N3WYF8-C/2/8cfff4b3da4360d0ea01d0ade1c93906},
      doi = {DOI: 10.1016/j.nima.2007.02.062}
    }
    					
    J. J. Barnard, R. J. Briggs, D. A. Callahan, R. C. Davidson, A. Friedman, L. Grisham, E. P. Lee, R. W. Lee, B. G. Logan, C. L. Olson, D. V. Rose, P. Santhanam, A. M. Sessler, J. W. Staples, M. Tabak, D. R. Welch, J. S. Wurtele & S. S. Yu Accelerator and Ion Beam Tradeoffs for Studies of Warm Dense Matter 2005 Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the, pp. 2568-2570  
    Abstract: One approach for heating a target to "Warm Dense Matter" conditions (similar, for example, to the interiors of giant planets or certain stages in inertial confinement fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam phase-space constraints, both at the injector, and at the final focus, and consideration of simple equations of state and relations for ion stopping, approximate conditions at the target foil may be calculated. Thus, target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We connect some of these basic parameters to help search the extensive parameter space (including ion mass, ion energy, total charge in beam pulse, beam emittance, target thickness and density.
    BibTeX:
    @article{1591185,
      author = {Barnard, J. J. and Briggs, R. J. and Callahan, D. A. and Davidson, R. C. and Friedman, A. and Grisham, L. and Lee, E. P. and Lee, R. W. and Logan, B. G. and Olson, C. L. and Rose, D. V. and Santhanam, P. and Sessler, A. M. and Staples, J. W. and Tabak, M. and Welch, D. R. and Wurtele, J. S. and Yu, S. S.},
      title = {Accelerator and Ion Beam Tradeoffs for Studies of Warm Dense Matter},
      journal = {Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the},
      year = {2005},
      pages = {2568-2570}
    }
    					
    G. Bekefi, J. S. Wurtele & I. H. Deutsch Free-electron-laser radiation induced by a periodic dielectric medium 1986 Phys. Rev. A
    Vol. 34 (2), pp. 1228-1236  
    Abstract: Stimulated emission by an unaccelerated electron beam propagating through a periodically modulated dielectric is studied. The laser gain in the low-gain regime is calculated for the case of a cold, tenuous electron beam by applying the Einstein-coefficient technique in the classical limit ħ→0. In the high-gain, strong-pump regime equations for the evolution of the electron beam dynamics and of the radiation are developed using a self-consistent, one-dimensional model for the interaction. Analytic calculations of the small-signal gain, and numerical computations of the nonlinear saturation characteristics, are presented.
    BibTeX:
    @article{PhysRevA.34.1228,
      author = {Bekefi, G. and Wurtele, J. S. and Deutsch, I. H.},
      title = {Free-electron-laser radiation induced by a periodic dielectric medium},
      journal = {Phys. Rev. A},
      publisher = {American Physical Society},
      year = {1986},
      volume = {34},
      number = {2},
      pages = {1228--1236},
      doi = {http://dx.doi.org/10.1103/PhysRevA.34.1228}
    }
    					
    M. Borland, B. Carlsten, J. Corlett, D. Douglas, W. Fawley, C. Geddes, G. Krat, J. Qiang, R. Ryne, J.-L. Vay, M. Venturini, J. Wurtele & A. Zholents Accelerator modeling for future FEL-based light sources 2009  
    BibTeX:
    @conference{,
      author = {M. Borland and B. Carlsten and J. Corlett and D. Douglas and W. Fawley and C. Geddes and G. Krat and J. Qiang and R. Ryne and J.-L. Vay and M. Venturini and J. Wurtele and A. Zholents},
      title = {Accelerator modeling for future FEL-based light sources},
      booktitle = {White Paper submitted to Accelerators for America Workshop},
      year = {2009}
    }
    					
    A. J. Brizard, H. Murayama & J. S. Wurtele Magnetic field generation from self-consistent collective neutrino-plasma interactions 2000 Phys. Rev. E
    Vol. 61 (4), pp. 4410-4421  
    Abstract: A Lagrangian formalism for self-consistent collective neutrino-plasma interactions is presented in which each neutrino species is described as a classical ideal fluid. The neutrino-plasma fluid equations are derived from a covariant relativistic variational principle in which finite-temperature effects are retained. This formalism is then used to investigate the generation of magnetic fields and the production of magnetic helicity as a result of collective neutrino-plasma interactions.
    BibTeX:
    @article{PhysRevE.61.4410,
      author = {Brizard, A. J. and Murayama, H. and Wurtele, J. S.},
      title = {Magnetic field generation from self-consistent collective neutrino-plasma interactions},
      journal = {Phys. Rev. E},
      publisher = {American Physical Society},
      year = {2000},
      volume = {61},
      number = {4},
      pages = {4410--4421},
      doi = {http://dx.doi.org/10.1103/PhysRevE.61.4410}
    }
    					
    A. J. Brizard & J. S. Wurtele Lagrangian formulation for neutrino-plasma interactions 1999 Phys. of Plasma
    Vol. 6 (4), pp. 1323-1328  
    Abstract: A Lagrangian formalism is used to derive coupled nonlinear equations for collective interactions between an intense neutrino flux and a relativistic cold plasma fluid with multiple particle species. In order to focus on the self-consistent (collective) treatment of neutrino--plasma interactions, quantum effects are ignored throughout and the (spinless) neutrinos are represented by a complex-valued Klein--Gordon scalar field. Through the application of Noether's method, the conservation laws for energy, momentum and wave action are derived explicitly. The transfer of energy, momentum and wave action between the neutrinos and the electromagnetic-plasma is discussed in the context of astrophysical applications (e.g., type II supernova explosions).
    BibTeX:
    @article{brizard:1323,
      author = {Alain J. Brizard and Jonathan S. Wurtele},
      title = {Lagrangian formulation for neutrino--plasma interactions},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {1999},
      volume = {6},
      number = {4},
      pages = {1323-1328},
      url = {http://link.aip.org/link/?PHP/6/1323/1},
      doi = {http://dx.doi.org/10.1063/1.873373}
    }
    					
    C. B. Schroeder, P. B. Lee, J. S. Wurtele, E. Esarey & W. P. Leemans Study of Laser Injection of Electrons into Plasma Wakefields 1998 (WEP18G)  
    Abstract: A proposed laser-lasma based electron source [1] using laser triggered injection of electrons is examined. the source generates ultashort electron bunches by dephasing background plasma electrons undergoing fluid oscillations in a plasma wake. The plasma electrons are dephased by colliding two counter-propagating laser pulses. Laser intensity thresholds for trapping and optimal wake phase for injection are calculated. Numerical simulations of test particles, with prescibed plasma and laser fields, are used to verify analytic predictions and to characterize the quality of the electron bunches.
    BibTeX:
    @conference{Schroeder:WEP18G,
      author = {C. B. Schroeder, and P. B. Lee, and J. S. Wurtele, and E. Esarey, and W. P. Leemans},
      title = {Study of Laser Injection of Electrons into Plasma Wakefields},
      year = {1998},
      number = {WEP18G},
      note = {Contributed to European Particle Accelerator Conference (EPAC 98), Stockholm, Sweden, 22-26 Jun 1998}
    }
    					
    C.M. Celata, A. M. Sessler, P. B. Lee, B. A. Shadwick & J. S. Wurtele A Moment Equation Approach to a Muon Collider Cooling Lattice 1998 (THP23C)  
    Abstract: Equations are derived which describe the evolution of the second order moments of the beam distribution function in the ionization cooling section of a muon collider. Ionization energy loss, multiple scattering, and magnetic fields have been included, but forces are linearized. A comuter code using the equations agrees well with tracking calculations. The code is extremely fast, and can be used for preliminary design, where such issues as beam halo, which must be explored using a tracking code, are not the focus.
    BibTeX:
    @conference{Celata:THP23C,
      author = {C.M. Celata, and A. M. Sessler, and P. B. Lee, and B. A. Shadwick, and J. S. Wurtele},
      title = {A Moment Equation Approach to a Muon Collider Cooling Lattice},
      year = {1998},
      number = {THP23C},
      note = {Contributed to European Particle Accelerator Conference (EPAC 98), Stockholm, Sweden, 22-26 Jun 1998}
    }
    					
    P. Catravas, W. P. Leemans, J. S. Wurtele, M. S. Zolotorev, M. Babzien, I. Ben-Zvi, Z. Segalov, X.-J. Wang & V. Yakimenko Measurement of Electron-Beam Bunch Length and Emittance Using Shot-Noise-Driven Fluctuations in Incoherent Radiation 1999 Phys. Rev. Lett.
    Vol. 82 (26), pp. 5261-5264  
    Abstract: Longitudinal and transverse phase space information has been obtained from a statistical analysis of fluctuations in the radiation spectrum of an electron bunch. Uncorrelated shot noise fluctuations in longitudinal beam density result in incoherent radiation with a spectrum that consists of spikes, with width inversely proportional to the bunch length. Measurements were performed at λ = 620 nm on a 1--5 ps long, 44 MeV bunch propagating through a wiggler. Bunch length and emittance obtained with this single shot technique agree with independent measurements.
    BibTeX:
    @article{PhysRevLett.82.5261,
      author = {Catravas, P. and Leemans, W. P. and Wurtele, J. S. and Zolotorev, M. S. and Babzien, M. and Ben-Zvi, I. and Segalov, Z. and Wang, X.-J. and Yakimenko, V.},
      title = {Measurement of Electron-Beam Bunch Length and Emittance Using Shot-Noise-Driven Fluctuations in Incoherent Radiation},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1999},
      volume = {82},
      number = {26},
      pages = {5261--5264},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.82.5261}
    }
    					
    C. L. Cesar, G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins & L. V. J�rgensen Antihydrogen Physics at ALPHA/CERN. 2009 Canadian Journal of Physics
    Vol. 87 (7), pp. 791 - 797  
    Abstract: Cold antihydrogen has been produced at CERN (Amoretti et al. (Nature, 419, 456 (2002)), Gabrielse et al. (Phys. Rev. Lett. 89, 213401 (2002))), with the aim of performing a high-precision spectroscopic comparison with hydrogen as a test of the CPT symmetry. Hydrogen, a unique system used for the development of quantum mechanics and quantum electrodynamics, has been continuously used to produce high-precision tests of theories and measurements of fundamental constants and can lead to a very sensitive search for CPT violation. After the initial production of cold antihydrogen atoms by the ATHENA group, the ALPHA Collaboration (http://alpha.web.cern.ch/) has set forth on an experiment to trap and perform high-resolution laser spectroscopy on the 1S-2S transition of both atoms. In this contribution, we will review the motivations, goals, techniques, and recent developments towards this fundamental physics test. We present new discussion on predicted lineshapes for the 1S-2S spectroscopy of trapped atoms in a regime not discussed before. Nous avons produit de l?anti-hydrog�ne au CERN (Amoretti et al. (Nature, 419, 456 (2002)), Gabrielse et al. (Phys. Rev. Lett. 89, 213401 (2002))), pour faire des comparaisons spectroscopiques de haute pr�cision avec l?hydrog�ne dans le cadre d?un test de la sym�trie CPT. L?hydrog�ne, qui a jou� un r�le unique dans le d�veloppement de la m�canique quantique et de l?�lectrodynamique quantique, a �t� utilis� continuellement dans des tests de haute pr�cision des th�ories et des mesures des constantes fondamentales et peut nous conduire � une recherche tr�s pr�cise de la violation CPT. Apr�s que le groupe ATHENA ait produit l?anti-hydrog�ne froid, l?�quipe ALPHA (http://alpha.web.cern.ch/) a d�velopp� un montage pour pi�ger les deux types d?atome et faire des mesures de spectroscopie laser de haute pr�cision des transitions 1S-2S dans les deux types d?atomes. Nous passons ici en revue les motivations, les buts, les techniques et les d�veloppements r�cents de ce test fondamental en physique. Nous pr�sentons de nouvelles id�es sur la forme des lignes en spectroscopie 1S-2S pour des atomes pi�g�s dans un r�gime qui n?a pas encore �t� discut�.
    BibTeX:
    @article{4476090820090701,
      author = {Cesar, C. L. and Andresen, G. B. and Bertsche, W. and Bowe, P. D. and Bray, C. C. and Butler, E. and Chapman, S. and Charlton, M. and Fajans, J. and Fujiwara, M. C. and Funakoshi, R. and Gill, D. R. and Hangst, J. S. and Hardy, W. N. and Hayano, R. S. and Hayden, M. E. and Humphries, A. J. and Hydomako, R. and Jenkins, M. J. and J�rgensen, L. V.},
      title = {Antihydrogen Physics at ALPHA/CERN.},
      journal = {Canadian Journal of Physics},
      year = {2009},
      volume = {87},
      number = {7},
      pages = {791 - 797},
      url = {http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=44760908&site=ehost-live}
    }
    					
    P. J. Channell, A. M. Sessler & J. S. Wurtele On the density oscillations of a warm particle bunch 1983 Physics of Fluids
    Vol. 26 (8), pp. 2281-2291  
    Abstract: The density oscillations of warm particle bunches is investigated theoretically. Two different mathematical approaches are employed to derive the basic equation describing density oscillations; one is a fluid approach and the second is a more general Green's function formulation. The motion is analyzed in first-order perturbation theory where it is shown, under the assumption of no degeneracy, that there are only stable oscillations. Second-order perturbation theory gives damping of the motion. The perturbation theory is examined, and a criterion is exhibited for its proper use. Thus, when the resistivity is small enough (but nonzero) the motion is stable, but when the resistivity is large the motion is essentially unstable with a growth rate which is that of an unbunched beam. The criterion is approximately evaluated using a model for a bunched beam.
    BibTeX:
    @article{channell:2281,
      author = {Paul J. Channell and Andrew M. Sessler and Jonathan S. Wurtele},
      title = {On the density oscillations of a warm particle bunch},
      journal = {Physics of Fluids},
      publisher = {AIP},
      year = {1983},
      volume = {26},
      number = {8},
      pages = {2281-2291},
      url = {http://link.aip.org/link/?PFL/26/2281/1},
      doi = {http://dx.doi.org/10.1063/1.864386}
    }
    					
    P. J. Channell, A. M. Sessler & J. S. Wurtele The longitudinal stability of intense nonrelativistic particle bunches in resistive structures 1981 Applied Physics Letters
    Vol. 39 (4), pp. 359-361  
    Abstract: The longitudinal stability of intense particle bunches is investigated theoretically in the limit of small wall resistivity compared to total reactance. It is shown that both in the absence of resistivity and to lowest order in the resistance that an intense bunch is stable against longitudinal collective modes. An expression is derived for the lowest order instability rate. Application of these results are made to drivers for heavy ion inertial fusion.
    BibTeX:
    @article{channell:359,
      author = {Paul J. Channell and Andrew M. Sessler and Jonathan S. Wurtele},
      title = {The longitudinal stability of intense nonrelativistic particle bunches in resistive structures},
      journal = {Applied Physics Letters},
      publisher = {AIP},
      year = {1981},
      volume = {39},
      number = {4},
      pages = {359-361},
      url = {http://link.aip.org/link/?APL/39/359/1},
      doi = {http://dx.doi.org/10.1063/1.92729}
    }
    					
    A. E. Charman Random Aspects of Beam Physics and Laser-Plasma Interactions 2007 School: University of California at Berkeley  
    BibTeX:
    @phdthesis{Charman,
      author = {Charman, A. E.},
      title = {Random Aspects of Beam Physics and Laser-Plasma Interactions},
      school = {University of California at Berkeley},
      year = {2007}
    }
    					
    A. E. Charman, G. Penn & J. S. Wurtele M. Conde & C. Eyberger (Hrsg.) A Hilbert-Space Variational Principle for Spontaneous Wiggler and Synchrotron Radiation 2006 Advanced Accelerator Concepts: 12th Advanced Accelerator Concepts Workshop
    Vol. 877 (1), pp. 381-387  
    Abstract: Within the framework of Hilbert space theory, we have developed a maximum-power variational principle applicable to classical spontaneous radiation from prescribed classical harmonic current sources. A simple proof is summarized for the case of three-dimensional fields propagating in vacuum, and specialization to the case of paraxial optics is discussed. The techniques have been developed to model undulator radiation from relativistic electron beams (for which an example involving high harmonic generation is reviewed), but are more broadly applicable to synchrotron or other radiation problems, and may generalize to certain structured media.
    BibTeX:
    @conference{charman:381,
      author = {A. E. Charman and G. Penn and J. S. Wurtele},
      title = {A Hilbert-Space Variational Principle for Spontaneous Wiggler and Synchrotron Radiation},
      journal = {Advanced Accelerator Concepts: 12th Advanced Accelerator Concepts Workshop},
      publisher = {AIP},
      year = {2006},
      volume = {877},
      number = {1},
      pages = {381-387},
      url = {http://link.aip.org/link/?APC/877/381/1},
      doi = {http://dx.doi.org/10.1063/1.2409159}
    }
    					
    A. E. Charman & J. S. Wurtele Quantum Mechanical Treatment of Transit-Time Optical Stochastic Cooling of Muons 2009  
    Abstract: Ultra-fast stochastic cooling would be desirable in certain applications, for example, in order to boost final luminosity in a muon collider or neutrino factory, where short particle lifetimes severely limit the total time available to reduce beam phase space. But fast cooling requires very high-bandwidth amplifiers so as to limit the incoherent heating effects from neighboring particles. A method of transit-time optical stochastic cooling has been proposed which would employ high-gain, high-bandwidth, solid-state lasers to amplify the spontaneous radiation from the charged particle bunch in a strong-field magnetic wiggler. This amplified light is then fed back onto the same bunch inside a second wiggler, with appropriate phase delay to effect cooling. But before amplification, the usable signal from any one particle is quite small, on average much less than one photon per pass, suggesting that the radiation should be treated quantum mechanically, and raising doubts as to whether this weak signal even contains sufficient phase information necessary for cooling, and whether it can be reliably amplified to provide the expected cooling on each pass. A careful examination of the dynamics, where the radiation and amplification processes are treated quantum mechanically, indicates that fast cooling is in principle possible, with cooling rates which essentially agree with classical calculations, provided that the effects of the unavoidable amplifier noise are included. Thus, quantum mechanical uncertainties do not present any insurmountable obstacles to optical cooling, but do establish a lower limit on cooling rates and achievable emittances.
    BibTeX:
    @misc{charman-2009,
      author = {A. E. Charman and J. S. Wurtele},
      title = {Quantum Mechanical Treatment of Transit-Time Optical Stochastic Cooling of Muons},
      year = {2009},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:0905.0485}
    }
    					
    A. E. Charman & J. S. Wurtele A Hilbert-space formulation of and variational principle for spontaneous wiggler radiation 2005  
    Abstract: Within the framework of Hilbert space theory, we derive a maximum-power variational principle applicable to classical spontaneous radiation from prescribed harmonic current sources. Results are first derived in the paraxial limit, then appropriately generalized to non-paraxial situations. The techniques were developed within the context of undulator radiation from relativistic electron beams, but are more broadly applicable.
    BibTeX:
    @misc{charman-2005,
      author = {A. E. Charman and J. S. Wurtele},
      title = {A Hilbert-space formulation of and variational principle for spontaneous wiggler radiation},
      year = {2005},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:physics/0501018}
    }
    					
    Chattopadhyay, S., Whittum, D. & J. S. Wurtele Summer Study on the New Directions in High-energy Physics (Snowmass 1996), Snowmass, Colorado Advanced Accelerator Technologies - A Snowmass '96 Subgroup Summary 1996  
    BibTeX:
    @conference{Chattopadhyay:539745,
      author = {Chattopadhyay, S., and Whittum, D., and Wurtele, J. S.},
      title = {Advanced Accelerator Technologies - A Snowmass '96 Subgroup Summary},
      year = {1996},
      note = {Contributed to DPF / DPB, Snowmass, Colorado, 25 Jun - 12 July 1996},
      doi = {OSTI/539745}
    }
    					
    C. Chen, B. G. Danly, G. Shvets & J. S. Wurtele Effect of longitudinal space-charge waves of a helical relativistic electron beam on the cyclotron maser instability 1992 Plasma Science, IEEE Transactions on
    Vol. 20 (3), pp. 149-154  
    Abstract: The influence of the longitudinal space-charge waves of a coherently gyrophased helical relativistic electron beam on the cyclotron maser instability is investigated in a cylindrical waveguide configuration using a three-dimensional kinetic theory. A dispersion relation that includes waveguide effects is derived. The stability properties of the cyclotron maser interaction are examined in detail. It is shown that, in general, the effects of space-charge waves on a coherently gyrophased beam are suppressed in a waveguide geometry, in comparison with an ideal one-dimensional cyclotron maser with similar beam parameters
    BibTeX:
    @article{142814,
      author = {Chen, C. and Danly, B. G. and Shvets, G. and Wurtele, J. S.},
      title = {Effect of longitudinal space-charge waves of a helical relativistic electron beam on the cyclotron maser instability},
      journal = {Plasma Science, IEEE Transactions on},
      year = {1992},
      volume = {20},
      number = {3},
      pages = {149-154},
      doi = {http://dx.doi.org/10.1109/27.142814}
    }
    					
    C. Chen, J. A. Davies, G. Zhang & J. S. Wurtele Large-amplitude traveling electromagnetic waves in collisionless magnetoplasmas 1992 Phys. Rev. Lett.
    Vol. 69 (1), pp. 73-76  
    Abstract: A class of exact large-amplitude traveling-wave solutions to the nonlinear Vlasov-Maxwell equations describing a one-dimensional collisionless magnetized plasma is obtained. These waves are complementary to the electrostatic Bernstein-Greene-Kruskal modes and can be classified as nonlinear fast electromagnetic waves and (slow) electromagnetic whistler waves. The wave characteristics are discussed for the case of a trapped-particle distribution function.
    BibTeX:
    @article{PhysRevLett.69.73,
      author = {Chen, C. and Davies, J. A. and Zhang, G. and Wurtele, J. S.},
      title = {Large-amplitude traveling electromagnetic waves in collisionless magnetoplasmas},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1992},
      volume = {69},
      number = {1},
      pages = {73--76},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.69.73}
    }
    					
    C. Chen & J. S. Wurtele Linear and nonlinear theory of cyclotron autoresonance masers with multiple waveguide modes 1991 Physics of Fluids B: Plasma Physics
    Vol. 3 (8), pp. 2133-2148  
    Abstract: The interaction of multiple waveguide modes with a relativistic electron beam in an overmoded, single-frequency, cyclotron autoresonance maser amplifier is analyzed using a nonlinear self-consistent model and kinetic theory. It is shown analytically, and confirmed by simulation, that all of the coupled waveguide modes grow at the spatial growth rate of the dominant unstable mode, but suffer different launching losses which depend upon detuning. The phases of coupled modes are locked in the exponential gain regime, and remain approximately locked for some finite interaction length beyond saturation. The saturated power in each mode is found to be insensitive to the input modal radio-frequency (rf) power distribution, but sensitive to detuning. Simulations indicate that the saturated fractional rf power in a given mode reaches a maximum at its resonant magnetic field, and then decreases rapidly off resonance. Good agreement is found between the simulations and the kinetic theory in the linear regime.
    BibTeX:
    @article{chen:2133,
      author = {Chiping Chen and Jonathan S. Wurtele},
      title = {Linear and nonlinear theory of cyclotron autoresonance masers with multiple waveguide modes},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1991},
      volume = {3},
      number = {8},
      pages = {2133-2148},
      url = {http://link.aip.org/link/?PFB/3/2133/1},
      doi = {http://dx.doi.org/10.1063/1.859626}
    }
    					
    C. Chen & J. S. Wurtele Multimode interactions in cyclotron autoresonance maser amplifiers 1990 Phys. Rev. Lett.
    Vol. 65 (27), pp. 3389-3392  
    Abstract: The interaction of transverse eigenmodes with a relativistic electron beam is analyzed in an overmoded cyclotron autoresonance maser amplifier, using a nonlinear self-consistent model and kinetic theory. It is shown that all of the coupled modes grow with the dominant unstable mode at the same growth rate, but suffer different launching losses. The phases of coupled modes are locked in the linear and nonlinear regimes. Simulations indicate that the rf power distribution among the interacting modes at saturation is insensitive to input power distribution but sensitive to detuning.
    BibTeX:
    @article{PhysRevLett.65.3389,
      author = {Chen, Chiping and Wurtele, Jonathan S.},
      title = {Multimode interactions in cyclotron autoresonance maser amplifiers},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1990},
      volume = {65},
      number = {27},
      pages = {3389--3392},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.65.3389}
    }
    					
    C. Chen & J. S. Wurtele Efficiency enhancement in cyclotron autoresonance maser amplifiers by magnetic field tapering 1989 Phys. Rev. A
    Vol. 40 (1), pp. 489-492  
    Abstract: The efficiency of cyclotron autoresonance maser (CARM) amplifiers with piecewise linear tapering of the magnetic field is analyzed. In the low-current limit, we find that increasing the magnetic field substantially enhances the efficiency if an effective detuning parameter is positive, while decreasing the magnetic field is advantageous when the detuning parameter is negative. For high-current, high-gain, CARM operation the efficacy of tapering is found to be reduced in a parameter regime where the saturation wave amplitude becomes of the order of an effective detuning parameter.
    BibTeX:
    @article{Chen1989,
      author = {Chen, C. and Wurtele, J. S.},
      title = {Efficiency enhancement in cyclotron autoresonance maser amplifiers by magnetic field tapering},
      journal = {Phys. Rev. A},
      publisher = {American Physical Society},
      year = {1989},
      volume = {40},
      number = {1},
      pages = {489--492},
      doi = {http://dx.doi.org/10.1103/PhysRevA.40.489}
    }
    					
    S. C. Chen, B. G. Danly, J. Gonichon, C. L. Lin, R. J. Temkin, S. R. Trotz & J. S. Wurtele High power testing of a 17 GHz photocathode RF gun 1995 Particle Accelerator Conference, 1995., Proceedings of the 1995
    Vol. 2, pp. 893-895  
    Abstract: We report experimental high power test results on a high gradient 17 GHz RF photocathode gun. The 1½ cell, π-mode, copper cavity was tested with 5-10 MW, 100 ns, 17.145 GHz pulses from a 24 M W Haimson Research Corp. klystron. A maximum surface electric field of 250 MeV/m was achieved corresponding to an on-axis gradient of 150 MeV/m. The gradient was verified by a preliminary electron beam energy measurement. Conditioning with ~105 shots resulted in a low field emission current, less than 6 mA. Future research will concentrate on measurements of the quality of electron beams produced by ps laser photoemission
    BibTeX:
    @article{505073,
      author = {Chen, S. C. and Danly, B. G. and Gonichon, J. and Lin, C. L. and Temkin, R. J. and Trotz, S. R. and Wurtele, J. S.},
      title = {High power testing of a 17 GHz photocathode RF gun},
      journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995},
      year = {1995},
      volume = {2},
      pages = {893-895},
      doi = {http://dx.doi.org/10.1109/PAC.1995.505073}
    }
    					
    S. C. Chen, J. Gonichon, L. C. L. Lin, R. J. Temkin, S. Trotz, B. G. Danly & J. S. Wurtele High gradient acceleration in a 17 GHz photocathode RF gun 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 4, pp. 2575-2577  
    Abstract: The physics and technological issues involved in high gradient particle acceleration at high microwave (RF) frequencies are under study at MIT. The 17 GHz photocathode RF gun has a 1½ cell room temperature copper cavity with a peak accelerating gradient of about 250 MV/m. The anticipated beam parameters, when operating with a photoemission cathode, are: energy 2 MeV, normalized emittance 0.43 π mm-mrad, energy spread 0.18%, bunch charge 0.1 nC, and bunch length 0.39 ps. The goal is to study particle acceleration at high field gradients and to generate high quality electron beams for potential applications in next generation linear colliders and free electron lasers. The experimental setup and status are described
    BibTeX:
    @article{309391,
      author = {Chen, S. C. and Gonichon, J. and Lin, L. C. -L. and Temkin, R. J. and Trotz, S. and Danly, B. G. and Wurtele, J. S.},
      title = {High gradient acceleration in a 17 GHz photocathode RF gun},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {4},
      pages = {2575-2577},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309391}
    }
    					
    W. Cheng, Y. Avitzour, Y. Ping, S. Suckewer, N. J. Fisch, M. S. Hur & J. S. Wurtele Reaching the nonlinear regime of Raman amplification of ultrashort laser pulses 2005 Phys. Rev. Lett.
    Vol. 94 (4)  
    Abstract: The intensity of a subpicosecond laser pulse was amplified by a factor of up to 1000 using the Raman backscatter interaction in a 2 mm long gas jet plasma. The process of Raman amplification reached the nonlinear regime, with the intensity of the amplified pulse exceeding that of the pump pulse by more than an order of magnitude. Features unique to the nonlinear regime such as gain saturation, bandwidth broadening, and pulse shortening were observed. Simulation and theory are in qualitative agreement with the measurements.
    BibTeX:
    @article{ISI:000226779000033,
      author = {Cheng, W. and Avitzour, Y. and Ping, Y. and Suckewer, S. and Fisch, N. J. and Hur, M. S. and Wurtele, J. S.},
      title = {Reaching the nonlinear regime of Raman amplification of ultrashort laser pulses},
      journal = {Phys. Rev. Lett.},
      year = {2005},
      volume = {94},
      number = {4},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.94.045003}
    }
    					
    W.-H. Cheng, A. M. Sessler, W. C. Turner & J. S. Wurtele Control of longitudinal collective behavior in the muon collider rings 1997 Particle Accelerator Conference, 1997. Proceedings of the 1997
    Vol. 1, pp. 422-424  
    Abstract: The longitudinal single bunch collective effects in a Muon Collider ring are theoretically examined. The situation involves an intense bunch, a short bunch, a small momentum compaction, a rather large impedance compared with the stability threshold criterion, and a luminosity life time limited by muon decay to a thousand turns. Qualitative descriptions of stability are given and a scaling law for the instability threshold is derived. Numerical simulation results for the impedance-related instabilities are given for two cases of current interest-a 250 GeV×250 GeV demonstration machine and a 2 TeV×2 TeV high energy machine. The results of these simulations are in good agreement with the predictions of the scaling law and show that the longitudinal collective effects are controllable with a proper choice of parameters (viz. RF voltage, RF frequency, linear and non-linear longitudinal chromaticity)
    BibTeX:
    @article{749676,
      author = {Wen-Hao Cheng and Sessler, A. M. and Turner, W. C. and Wurtele, J. S.},
      title = {Control of longitudinal collective behavior in the muon collider rings},
      journal = {Particle Accelerator Conference, 1997. Proceedings of the 1997},
      year = {1997},
      volume = {1},
      pages = {422-424},
      doi = {http://dx.doi.org/10.1109/PAC.1997.749676}
    }
    					
    W.-H. Cheng, A. M. Sessler & J. S. Wurtele Increase of the transverse strong head-tail stability threshold by an alternating chromaticity 1997 Particle Accelerator Conference, 1997. Proceedings of the 1997
    Vol. 2, pp. 1614-1616  
    Abstract: It has been shown that the transverse head-tail instability can be suppressed by modulating the chromaticity over a synchrotron period. In this work, we demonstrate that the threshold of the strong head-tail instability can be significantly increased by the alternating chromaticity (AC). We present results of multi-particle simulation and a new criterion for the SHT instability
    BibTeX:
    @article{750776,
      author = {Wen-Hao Cheng and Sessler, A. M. and Wurtele, J. S.},
      title = {Increase of the transverse strong head-tail stability threshold by an alternating chromaticity},
      journal = {Particle Accelerator Conference, 1997. Proceedings of the 1997},
      year = {1997},
      volume = {2},
      pages = {1614-1616},
      doi = {http://dx.doi.org/10.1109/PAC.1997.750776}
    }
    					
    W.-H. Cheng, A. M. Sessler & J. S. Wurtele Varying chromaticity: A damping mechanism for the transverse head-tail instability 1997 Phys. Rev. E
    Vol. 56 (4), pp. 4695-4709  
    Abstract: A detailed analytical and numerical study of the suppression of the transverse head-tail instability by modulating the chromaticity over a synchrotron period is presented. We find that a threshold can be developed, and it can be increased to a value larger than the strong head-tail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physical mechanisms of the damping scheme are rotation of the head-tail phase such that the instability does not occur, and Landau damping due to the incoherent betatron tune spread generated by the varying chromaticity.
    BibTeX:
    @article{PhysRevE.56.4695,
      author = {Cheng, Wen-Hao and Sessler, Andrew M. and Wurtele, Jonathan S.},
      title = {Varying chromaticity: A damping mechanism for the transverse head-tail instability},
      journal = {Phys. Rev. E},
      publisher = {American Physical Society},
      year = {1997},
      volume = {56},
      number = {4},
      pages = {4695--4709},
      doi = {http://dx.doi.org/10.1103/PhysRevE.56.4695}
    }
    					
    W.-H. Cheng, A. M. Sessler & J. S. Wurtele Damping of the Transverse Head-Tail Instability by Periodic Modulation of the Chromaticity 1997 Phys. Rev. Lett.
    Vol. 78 (24), pp. 4565-4568  
    Abstract: An analytical and numerical study of the suppression of the transverse head-tail instability by modulating the chromaticity over a synchrotron period is presented. We find that a threshold can be developed, and it can be increased to a value larger than the strong head-tail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physical mechanisms of the damping scheme are rotation of the head-tail phase such that the instability does not occur, and Landau damping due to the incoherent betatron tune spread generated by the varying chromaticity.
    BibTeX:
    @article{PhysRevLett.78.4565,
      author = {Cheng, Wen-Hao and Sessler, Andrew M. and Wurtele, Jonathan S.},
      title = {Damping of the Transverse Head-Tail Instability by Periodic Modulation of the Chromaticity},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1997},
      volume = {78},
      number = {24},
      pages = {4565--4568},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.78.4565}
    }
    					
    T. C. Chiou, T. Katsouleas, C. Decker, W. B. Mori, J. S. Wurtele, G. Shvets & J. J. Su Laser wake-field acceleration and optical guiding in a hollow plasma channel 1995 Phys. of Plasma
    Vol. 2 (1), pp. 310-318  
    Abstract: The accelerating and focusing wake fields that can be excited by a short laser pulse in a hollow underdense plasma are examined. The evacuated channel in the plasma serves as an optical fiber to guide the laser pulse over many Rayleigh lengths. Wake fields excited by plasma current at the edge of the channel extend to the center where they may be used for ultrahigh gradient acceleration of particles over long distances. The wake field and equilibrium laser profiles are found analytically and compared to two-dimensional (2-D) particle-in-cell (PIC) simulations. Laser propagation is simulated over more than ten Rayleigh lengths. The accelerating gradients on the axis of a channel of radius c/omegap are of order of one-half of the gradients in a uniform plasma.
    BibTeX:
    @article{chiou:310,
      author = {T. C. Chiou and T. Katsouleas and C. Decker and W. B. Mori and J. S. Wurtele and G. Shvets and J. J. Su},
      title = {Laser wake-field acceleration and optical guiding in a hollow plasma channel},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {1995},
      volume = {2},
      number = {1},
      pages = {310-318},
      url = {http://link.aip.org/link/?PHP/2/310/1},
      doi = {http://dx.doi.org/10.1063/1.871107}
    }
    					
    R. Chu, J. S. Wurtele, J. Notte, A. J. Peurrung & J. Fajans Pure electron plasmas in asymmetric traps 1993 Physics of Fluids B: Plasma Physics
    Vol. 5 (7), pp. 2378-2386  
    Abstract: Pure electron plasmas are routinely confined within cylindrically symmetric Penning traps. In this paper the static and dynamic properties of plasmas confined in traps with applied electric field asymmetries are investigated. Simple analytical theories are derived and used to predict the shapes of the stable noncircular plasma equilibria observed in experiments. Both analytical and experimental results agree with those of a vortex-in-cell simulation. For an [script l]=1 diocotron mode in a cylindrically symmetric trap, the plasma rotates as a rigid column in a circular orbit. In contrast, plasmas in systems with electric field asymmetries are shown to have an analog to the [script l]=1 mode in which the shape of the plasma changes as it rotates in a noncircular orbit. These bulk plasma features are studied with a Hamiltonian model. It is seen that, for a small plasma, the area enclosed by the orbit of the center of charge is an invariant when electric field perturbations are applied adiabatically. This invariant has been observed experimentally. The breaking of the invariant is also studied. The dynamic Hamiltonian model is also used to predict the shape and frequency of the large amplitude [script l]=1 and [script l]=2 diocotron modes in symmetric traps.
    BibTeX:
    @article{chu:2378,
      author = {R. Chu and J. S. Wurtele and J. Notte and A. J. Peurrung and J. Fajans},
      title = {Pure electron plasmas in asymmetric traps},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1993},
      volume = {5},
      number = {7},
      pages = {2378-2386},
      url = {http://link.aip.org/link/?PFB/5/2378/1},
      doi = {http://dx.doi.org/10.1063/1.860721}
    }
    					
    A. Collaboration, G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, L. V. Jorgensen, S. J. Kerrigan, L. Kurchaninov, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. P. Povilus, P. Pusa, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf & Y. Yamazaki Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector 2009 Review of Scientific Instruments
    Vol. 80 (12), pp. 123701  
    Abstract: A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10?200 eV, <1?eV spread) antiproton extractions is compared to that of electrons and positrons.
    BibTeX:
    @article{Collaboration2009,
      author = {ALPHA Collaboration and G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and L. V. Jorgensen and S. J. Kerrigan and L. Kurchaninov and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. P. Povilus and P. Pusa and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and Y. Yamazaki},
      title = {Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector},
      journal = {Review of Scientific Instruments},
      publisher = {AIP},
      year = {2009},
      volume = {80},
      number = {12},
      pages = {123701},
      url = {http://link.aip.org/link/?RSI/80/123701/1},
      doi = {http://dx.doi.org/10.1063/1.3266967}
    }
    					
    J. Corlett, K. Baptiste, J. Byrd, P. Denes, R. Falcone, J. Feng, M. Graves, J. Kirz, D. Li, H. Padmore, C. Papadopoulos, G. Penn, J. Qiang, D. Robin, R. Ryne, F. Sanniblae, R. Schoeniein, J. Staples, C. Steier, T. V. Ecchione, M. Venturini, W. Wan, R. Wells, R, Wicox, J. Wurtele, A. Charman & E. Kur Design Studies for a VUV-soft X-ray FEL Facility at LBNL 2010  
    BibTeX:
    @conference{,
      author = {J.N. Corlett and K.M. Baptiste and J.M. Byrd and P. Denes and R.W. Falcone and J. Feng and M. Graves and J. Kirz and D. Li and H.A. Padmore and C. Papadopoulos and G. Penn and J. Qiang and D.S. Robin and R. Ryne and F. Sanniblae and R.W. Schoeniein and J.W. Staples and C. Steier and T. V. Ecchione and M. Venturini and W. Wan and R. Wells and R and Wicox and J. Wurtele and A. Charman and E. Kur},
      title = {Design Studies for a VUV-soft X-ray FEL Facility at LBNL},
      booktitle = {Proceeding of the First International Particle Accelerator Conference},
      year = {2010}
    }
    					
    B. Danly, G. Bekefi, R. Davidson, R. Temkin, T. Tran & J. S. Wurtele Principles of gyrotron powered electromagnetic wigglers for free-electron lasers 1987 Quantum Electronics, IEEE Journal of
    Vol. 23 (1), pp. 103-116  
    Abstract: The operation of free-electron lasers (FEL's) with axial electron beams and high-power electromagnetic wiggler fields such as those produced by high-power gyrotrons is discussed. The use of short wavelength electromagnetic wigglers in waveguides and resonant cavities can significantly reduce required electron beam voltages, resulting in compact FEL's. Gain calculations in the low- and high-gain Compton regime are presented, including the effects of emittance, transverse wiggler gradient, and electron temperature. Optimized scaling laws for the FEL gain and the required electromagnetic wiggler field power are discussed. Several possible configurations for FEL's with electro-magnetic wigglers powered by millimeter wavelength gyrotrons are presented. Gyrotron powered wigglers appear promising for operation of compact FEL's in the infrared regime using moderate energy (<10 MeV) electron beams.
    BibTeX:
    @article{1073205,
      author = {Danly, B. and Bekefi, G. and Davidson, R. and Temkin, R. and Tran, T. and Wurtele, J. S.},
      title = {Principles of gyrotron powered electromagnetic wigglers for free-electron lasers},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1987},
      volume = {23},
      number = {1},
      pages = {103-116}
    }
    					
    B. G. Danly, J. S. Wurtele, K. D. Pendergast & R. J. Temkin CARM driver for high frequency RF accelerators 1989 Particle Accelerator Conference, 1989. Accelerator Science and Technology., Proceedings of the 1989 IEEE
    Vol. 1, pp. 223-225  
    Abstract: The CARM (cyclotron autoresonance maser) is a promising source of microwave power for the next generation of linear collider. Designs for a high-power 17.136-GHz CARM amplifier, utilizing a 700-kV pulse modulator and a 1.2-MeV linear induction accelerator, are presented. These designs are attractive for a proof-of-principle CARM amplifier experiment. Interaction efficiencies are in the 30-50% range; higher efficiencies should be possible with nonlinear tapers
    BibTeX:
    @article{73129,
      author = {Danly, B. G. and Wurtele, J. S. and Pendergast, K. D. and Temkin, R. J.},
      title = {CARM driver for high frequency RF accelerators},
      journal = {Particle Accelerator Conference, 1989. Accelerator Science and Technology., Proceedings of the 1989 IEEE},
      year = {1989},
      volume = {1},
      pages = {223-225},
      doi = {http://dx.doi.org/10.1109/PAC.1989.73129}
    }
    					
    R. C. Davidson & J. S. Wurtele Influence of untrapped electrons on the sideband instability in a helical wiggler free electron laser 1987 Physics of Fluids
    Vol. 30 (9), pp. 2825-2838  
    Abstract: The detailed influence of an untrapped-electron population on the sideband instability in a helical wiggler free electron laser is investigated for small-amplitude perturbations about a constant-amplitude (a-hat 0s =const) primary electromagnetic wave with slowly varying equilibrium phase delta0s. A simple model is adopted in which all of the trapped electrons are deeply trapped, and the equilibrium motion of the untrapped electrons (assumed monoenergetic) is only weakly modulated by the ponderomotive potential. The theoretical model is based on the single-particle orbit equations together with Maxwell's equations and appropriate statistical averages. Moreover, the stability analysis is carried out in the ponderomotive frame, which leads to a substantial simplification in deriving the dispersion relation. Detailed stability properties are investigated over a wide range of dimensionless pump strength OmegaB /Gammab ck0 and fraction of untrapped electrons fu =n-hat u /n-hat b. When both trapped and untrapped electrons) are present, there are generally two types of unstable modes, referred to as the sideband mode, and the untrapped-electron mode. For fu =0, only the sideband instability is present. As fu is increased, the growth rate of the sideband instability decreases, whereas the growth rate of the untrapped-electron mode increases until only the untrapped-electron mode is unstable for fu =1. It is found that the characteristic maximum growth rate of the most unstable mode varies by only a small amount over the entire range of fu from fu =0 (no untrapped electrons to fu =1 (no trapped electrons). The present analysis suggests that the linear and nonlinear evolution of the beam electrons and radiation field may be substantially modified by the present of an untrapped-electron component when fu >~0.2.
    BibTeX:
    @article{davidson:2825,
      author = {Ronald C. Davidson and Jonathan S. Wurtele},
      title = {Influence of untrapped electrons on the sideband instability in a helical wiggler free electron laser},
      journal = {Physics of Fluids},
      publisher = {AIP},
      year = {1987},
      volume = {30},
      number = {9},
      pages = {2825-2838},
      url = {http://link.aip.org/link/?PFL/30/2825/1},
      doi = {http://dx.doi.org/10.1063/1.866047}
    }
    					
    R. C. Davidson & J. S. Wurtele Single-particle analysis of the free-electron laser sideband instability for primary electromagnetic wave with constant phase and slowly varying phase 1987 Physics of Fluids
    Vol. 30 (2), pp. 557-569  
    Abstract: Use is made of the single-particle orbit equations together with Maxwell's equations and appropriate statistical averages to investigate detailed properties of the sideband instability for a helical-wiggler free-electron laser with wiggler wavelength lambda0=2pi/k0=const and normalized wiggler amplitude aw=eB-hat w/mc2k0 =const. The model describes the nonlinear evolution of a right-circularly polarized primary electromagnetic wave with frequency omegas, wavenumber ks, and slowly varying amplitude a-hat s(z,t) and phase deltas(z,t) (eikonal approximation). The orbit and wave equations are analyzed in the ponderomotive frame (``primed'' variables) moving with velocity vp=omegas/(ks+k0) relative to the laboratory. Detailed properties of the sideband instability are investigated for small-amplitude perturbations about a quasisteady equilibrium state characterized by a-hat 0s =const (independent of z[script '] and t[script ']). Two cases are treated. The first case assumes constant equilibrium wave phase delta0s =const, which requires (for self-consistency) both untrapped- and trapped-electron populations satisfying <[summation]j exp[ik[script ']pzj0(t[script ']) +idelta0s]/gamma[script ']j>=0.Here kp=(ks+k0)/gammap is the wavenumber of the ponderomotive potential, z[script ']j0(t[script ']) is the equilibrium orbit, and gammajmc2 is the electron energy. The second case assumes that all of the electrons are deeply trapped, which requires a slow spatial variation of the equilibrium wave phase, [partial-derivative]delta0s/[partial-derivative]z[script ']=2Gamma0(Gamma0ck0/OmegaB)2 k[script ']p[not-equal]0. The resulting dispersion relations and detailed stability properties are found to be quite different in the two cases. Both the weak-pump and strong-pump regimes are considered.
    BibTeX:
    @article{davidson:557,
      author = {Ronald C. Davidson and Jonathan S. Wurtele},
      title = {Single-particle analysis of the free-electron laser sideband instability for primary electromagnetic wave with constant phase and slowly varying phase},
      journal = {Physics of Fluids},
      publisher = {AIP},
      year = {1987},
      volume = {30},
      number = {2},
      pages = {557-569},
      url = {http://link.aip.org/link/?PFL/30/557/1},
      doi = {http://dx.doi.org/10.1063/1.866353}
    }
    					
    R. C. Davidson, J. S. Wurtele & R. E. Aamodt Kinetic analysis of the sideband instability in a helical wiggler free-electron laser for electrons trapped near the bottom of the ponderomotive potential 1986 Phys. Rev. A
    Vol. 34 (4), pp. 3063-3076  
    Abstract: A kinetic formalism based on the Vlasov-Maxwell equations is used to investigate properties of the sideband instability for a tenuous, relativistic electron beam propagating through a constant-amplitude helical wiggler magnetic field (wavelength λ0=2π/k0 and normalized amplitude aw=eB^w/mc2k0). The analysis is carried out for perturbations about an equilibrium Bernstein-Greene-Kruskal state in which the distribution of beam electrons Gs(γ') and the wiggler magnetic field coexist in quasisteady equilibrium with a finite-amplitude, circularly polarized, primary electromagnetic wave (ωs,ks) with normalized amplitude as=eB^s/mc2ks and constant equilibrium wave phase.
    Particular emphasis is placed on calculating detailed properties of the sideband instability for the case where a uniform distribution of trapped electrons GsT(γ') is localized near the bottom of the ponderomotive potential moving with velocity vp=ωs/(ks+k0) relative to the laboratory frame. For harmonic numbers n≥2, it is found that stable (Imω=0) sideband oscillations exist for [ω-(k+k0)vp]2≊n2ΩB 2.
    Here, (ω,k) are the perturbation frequency and wave number in the laboratory frame, ΩB =[awasc2(kp')2/(γ ^ M')2γp2]1/2 is the bounce frequency, γ^ M'mc2 is the maximum energy of the trapped electrons in the ponderomotive frame, and kp' and γp are defined by kpsprime/emph>=(ks+k0)/γp and γp=(1-vp2/c2)-1/2. On the other hand, for the fundamental (n=1) mode, instability exists (Imω>0) over a wide range of system parameters ΩB/ck0≪1 and Γ0≪1, where Γ03=(aw2/4)(ω^pT 2/γp2c2k02)(1+v p/vp(γ^ M')3] and ω^pT=(4πn^Te2/m)1/2 is the plasma frequency of the trapped electrons.
    Moreover, the maximum growth rate and bandwidth of the sideband instability for the fundamental (n=1) mode exhibit a sensitive dependence on the normalized pump strength ΩB/Γ0k0c. .AE
    BibTeX:
    @article{PhysRevA.34.3063,
      author = {Davidson, Ronald C. and Wurtele, Jonathan S. and Aamodt, Richard E.},
      title = {Kinetic analysis of the sideband instability in a helical wiggler free-electron laser for electrons trapped near the bottom of the ponderomotive potential},
      journal = {Phys. Rev. A},
      publisher = {American Physical Society},
      year = {1986},
      volume = {34},
      number = {4},
      pages = {3063--3076},
      doi = {http://dx.doi.org/10.1103/PhysRevA.34.3063}
    }
    					
    A. C. DiRienzo, G. Bekefi, C. Chen & J. S. Wurtele Experimental and theoretical studies of a 35 GHz cyclotron autoresonance maser amplifier 1991 Physics of Fluids B: Plasma Physics
    Vol. 3 (7), pp. 1755-1765  
    Abstract: Experimental and theoretical studies of a cyclotron autoresonance maser (CARM) amplifier are reported. The measurements are carried out at a frequency of 35 GHz using a mildly relativistic electron beam (1.5 MeV, 130 A, 30 nsec) generated by a field emission electron gun followed by an emittance selector that removes the outer, hot electrons. Perpendicular energy is imparted to the electrons by means of a short bifilar helical wiggler. The entire system is immersed in a uniform axial magnetic field of 6--8 kG. With an input power of 17 kW at 35 GHz from a magnetron driver, the saturated power output is 12 MW in the lowest TE11 mode of a circular waveguide, corresponding to an electronic efficiency of 6.3%. The accompanying linear growth rate is 50 dB/m. When the system operates in the superradiant mode (in the absence of the magnetron driver) excitation of multiple waveguide modes is observed. A three-dimensional simulation code that has been developed to investigate the self-consistent interaction of the copropagating electromagnetic waveguide mode and the relativistic electron beam is in good agreement with the experimental observations.
    BibTeX:
    @article{dirienzo:1755,
      author = {A. C. DiRienzo and G. Bekefi and C. Chen and J. S. Wurtele},
      title = {Experimental and theoretical studies of a 35 GHz cyclotron autoresonance maser amplifier},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1991},
      volume = {3},
      number = {7},
      pages = {1755-1765},
      url = {http://link.aip.org/link/?PFB/3/1755/1},
      doi = {http://dx.doi.org/10.1063/1.859694}
    }
    					
    E. Esarey, C. B. Schroeder, B. A. Shadwick, J. S. Wurtele & W. P. Leemans Nonlinear Theory of Nonparaxial Laser Pulse Propagation in Plasma Channels 2000 Phys. Rev. Lett.
    Vol. 84 (14), pp. 3081-3084  
    Abstract: Nonparaxial propagation of ultrashort, high-power laser pulses in plasma channels is examined. In the adiabatic limit, pulse energy conservation, nonlinear group velocity, damped betatron oscillations, self-steepening, self-phase modulation, and shock formation are analyzed. In the nonadiabatic limit, the coupling of forward Raman scattering (FRS) and the self-modulation instability (SMI) is analyzed and growth rates are derived, including regimes of reduced growth. The SMI is found to dominate FRS in most regimes of interest.
    BibTeX:
    @article{PhysRevLett.84.3081,
      author = {Esarey, E. and Schroeder, C. B. and Shadwick, B. A. and Wurtele, J. S. and Leemans, W. P.},
      title = {Nonlinear Theory of Nonparaxial Laser Pulse Propagation in Plasma Channels},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {2000},
      volume = {84},
      number = {14},
      pages = {3081--3084},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.84.3081}
    }
    					
    E. Esarey, B. A. Shadwick, C. B. Schroeder, J. S. Wurtele & W. P. Leemans P. L. Colestock & S. Kelley (Hrsg.) Nonparaxial propagation of intense laser pulses in plasmas 2001 The ninth workshop on advanced accelerator concepts
    Vol. 569 (1), pp. 214-222  
    Abstract: Non-paraxial propagation of ultrashort, high power laser pulses in plasma channels is examined. In the adiabatic limit, pulse energy conservation, nonlinear group velocity, damped betatron oscillations, self-steepening, self-phase modulation, and shock formation are analyzed. In the non-adiabatic limit, the coupling of forward Raman scattering (FRS) and the self-modulation instability (SMI) is analyzed and growth rates are derived, including regimes of reduced growth. The SMI is found to dominate FRS in most regimes of interest.
    BibTeX:
    @conference{esarey:214,
      author = {E. Esarey and B. A. Shadwick and C. B. Schroeder and J. S. Wurtele and W. P. Leemans},
      title = {Nonparaxial propagation of intense laser pulses in plasmas},
      journal = {The ninth workshop on advanced accelerator concepts},
      publisher = {AIP},
      year = {2001},
      volume = {569},
      number = {1},
      pages = {214-222},
      url = {http://link.aip.org/link/?APC/569/214/1},
      doi = {http://dx.doi.org/10.1063/1.1384352}
    }
    					
    B. Faatz, W. Fawley, P. Pierini, S. Reiche, G. Travish, D. Whittum & J. S. Wurtele TDA3D: Updates and improvements to the widely used three-dimensional free electron laser simulation 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 393 (1-3), pp. 277-279  
    Abstract: TDA3D is a widely distributed and often used Free Electron Laser (FEL) simulation code. While a number of versions of TDA exist, this paper describes the official version which is well tested and supported. We describe the capabilities of the code emphasizing recent improvements and revisions. TDA3D is a steady-state (time-independent) amplifier code. The code self-consistently solves, after averaging over a wiggler period, the paraxial wave equation for the radiation field and the Lorentz equations of motion for the electrons. The paraxial wave equation includes diffraction and optical guiding. The calculation of the electron beam motion takes into account longitudinal bunching and transverse betatron oscillations, so that emittance, energy spread, and external focusing can be properly modeled. Recent additions to the simulation include the ability to model natural wiggler focusing in one or both planes, alternating gradient quadrupoles or sextupoles, and ion channels. The initial loading of the electron distribution can be controlled to allow for matching into focusing channels, improved quiet starts (non-correlated phase-space distributions), and arbitrary energy spread.
    BibTeX:
    @article{Faatz:1997fp,
      author = {Faatz, B. and Fawley, W. and Pierini, P. and Reiche, S. and Travish, G. and Whittum, D. and Wurtele, J. S.},
      title = {TDA3D: Updates and improvements to the widely used three-dimensional free electron laser simulation},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {393},
      number = {1-3},
      pages = {277--279},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPTFJX-79/1/758b57e271e9603fec436dad6a3993a7}
    }
    					
    J. Fajans, W. Bertsche, K. Burke, A. Deutsch, S. F. Chapman, K. Gomberoff, D. P. van der Werf & J. S. Wurtele M. Drewsen, U. Uggerhoj & H. Knudsen (Hrsg.) Simple loss scaling laws for quadrupoles and higher-order multipoles used in antihydrogen traps 2006 Non-Neutral Plasma Physics VI: Workshop on Non-Neutral Plasmas 2006
    Vol. 862 (1), pp. 176-180  
    Abstract: Simple scaling laws strongly suggest that for antihydrogen relevant parameters, quadrupole magnetic fields will transport particles into, or near to, the trap walls. Consequently quadrupoles are a poor choice for antihydrogen trapping. Higher order multipoles lead to much less transport.
    BibTeX:
    @conference{fajans:176,
      author = {J. Fajans and W. Bertsche and K. Burke and A. Deutsch and S. F. Chapman and K. Gomberoff and D. P. van der Werf and J. S. Wurtele},
      title = {Simple loss scaling laws for quadrupoles and higher-order multipoles used in antihydrogen traps},
      journal = {Non-Neutral Plasma Physics VI: Workshop on Non-Neutral Plasmas 2006},
      publisher = {AIP},
      year = {2006},
      volume = {862},
      number = {1},
      pages = {176-180},
      url = {http://link.aip.org/link/?APC/862/176/1},
      doi = {http://dx.doi.org/10.1063/1.2387922}
    }
    					
    J. Fajans, R. Chu & J. S. Wurtele Parametric studies of free-electron laser nonlinear ponderomotive trapping buckets 1991 Quantum Electronics, IEEE Journal of
    Vol. 27 (12), pp. 2546-2549  
    Abstract: Experimental and computational studies of free-electron lasers (FELs) operating at high input powers have been undertaken. These studies constitute a novel method of investigating saturation and trapping effects in free-electron lasers. Experiments and simulations show that when the input radiation power is increased to levels comparable to output power, the energy that maximizes the FEL gain shifts upwards. This effect is directly related to the height of the FEL ponderomotive trapping bucket (see J.S. Wurtele et al., 1990). By parametrically surveying the extent of this energy shift the authors observe the nonlinear trapping bucket phenomenon
    BibTeX:
    @article{104131,
      author = {Fajans, J. and Chu, R. and Wurtele, J. S.},
      title = {Parametric studies of free-electron laser nonlinear ponderomotive trapping buckets},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1991},
      volume = {27},
      number = {12},
      pages = {2546-2549},
      doi = {http://dx.doi.org/10.1109/3.104131}
    }
    					
    J. Fajans, G. Gabrielse, F. Robicheaux, A. Sessler & J. Wurtele Discovery science with low energy antiproton sources: The ELENA upgrade 2009  
    BibTeX:
    @conference{,
      author = {J. Fajans and G. Gabrielse and F. Robicheaux and A. Sessler and J. Wurtele},
      title = {Discovery science with low energy antiproton sources: The ELENA upgrade},
      booktitle = {White Paper submitted to Accelerators for America Workshop},
      year = {2009}
    }
    					
    J. Fajans, N. Madsen & F. Robicheaux Critical loss radius in a Penning trap subject to multipole fields 2008 Physics of Plasmas
    Vol. 15 (3), pp. 032108  
    Abstract: When particles in a Penning trap are subject to a magnetic multipole field, those beyond a critical radius will be lost. The critical radius depends on the history by which the field is applied, and can be much smaller if the particles are injected into a preexisting multipole than if the particles are subject to a ramped multipole. Both cases are relevant to ongoing experiments designed to trap antihydrogen.
    BibTeX:
    @article{Fajans2008,
      author = {J. Fajans and N. Madsen and F. Robicheaux},
      title = {Critical loss radius in a Penning trap subject to multipole fields},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2008},
      volume = {15},
      number = {3},
      pages = {032108},
      url = {http://link.aip.org/link/?PHP/15/032108/1},
      doi = {http://dx.doi.org/10.1063/1.2899306}
    }
    					
    J. Fajans & J. S. Wurtele Waveguide mode deformation in free-electron lasers 1989 Physics of Fluids B: Plasma Physics
    Vol. 1 (10), pp. 2073-2084  
    Abstract: The free-electron laser (FEL)-induced modifications to the vacuum waveguide modes are calculated for low-frequency FEL's. Typically, the mode modifications are large and exhibit complicated axial behaviors. In addition to the wave component with a near vacuum wavenumber, components at two upshifted wavenumbers must be analyzed. Electron beam surface charges and currents are also important. At low gain, effects from all three roots of the FEL dispersion relation must be included. The dominant modification is due to the electron beam space-charge wave.
    BibTeX:
    @article{fajans:2073,
      author = {J. Fajans and J. S. Wurtele},
      title = {Waveguide mode deformation in free-electron lasers},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1989},
      volume = {1},
      number = {10},
      pages = {2073-2084},
      url = {http://link.aip.org/link/?PFB/1/2073/1},
      doi = {http://dx.doi.org/10.1063/1.859072}
    }
    					
    J. Fajans & J. S. Wurtele Suppression of feedback oscillations in free-electron lasers 1988 Quantum Electronics, IEEE Journal of
    Vol. 24 (9), pp. 18005-18006  
    Abstract: The suppression of feedback oscillations in a free-electron laser (FEL) oscillator has been investigated. It is found, through numerical simulation that a narrow attenuating strip inserted in a waveguide will not reduce FEL performance at the desired frequency and will attenuate feedback oscillations. Simulations are presented for a 5-mm-wavelength FEL with a 40-dB attenuator inserted in the interaction region
    BibTeX:
    @article{7116,
      author = {Fajans, J. and Wurtele, J. S.},
      title = {Suppression of feedback oscillations in free-electron lasers},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1988},
      volume = {24},
      number = {9},
      pages = {18005-18006},
      doi = {http://dx.doi.org/10.1109/3.7116}
    }
    					
    J. Fajans, J. S. Wurtele, G. Bekefi, D. S. Knowles & K. Xu Nonlinear Power Saturation and Phase (Wave Refractive Index) in a Collective Free-Electron Laser Amplifier 1986 Phys. Rev. Lett.
    Vol. 57 (5), pp. 579-582  
    Abstract: We report measurements of the nonlinear radiation intensity and phase (wave refractive index) of a free-electron laser amplifier operating in the collective (Raman) regime. The laser generates up to ∼ 100 kW of rf power at a frequency of 9.3 GHz and with an efficiency of ∼ 10%. Power saturation, efficiency, synchrotron oscillations, and the rf phase are studied as functions of electron beam energy, current, and axial distance within the helical wiggler. Excellent agreement with nonlinear theory that takes cognizance of electron trapping in the combined ponderomotive and space-charge potential well is obtained.
    BibTeX:
    @article{PhysRevLett.57.579,
      author = {Fajans, J. and Wurtele, J. S. and Bekefi, G. and Knowles, D. S. and Xu, K.},
      title = {Nonlinear Power Saturation and Phase (Wave Refractive Index) in a Collective Free-Electron Laser Amplifier},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1986},
      volume = {57},
      number = {5},
      pages = {579--582},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.57.579}
    }
    					
    L. Friedland, F. Peinetti, W. Bertsche, J. Fajans & J. S. Wurtele Driven phase space holes and synchronized Bernstein, Greene, and Kruskal modes 2004 Phys. of Plasma
    Vol. 11 (9), pp. 4305-4317  
    Abstract: The excitation of synchronized Bernstein, Greene, and Kruskal (BGK) modes in a pure electron plasma confined in Malmberg--Penning trap is studied. The modes are excited by controlling the frequency of an oscillating external potential. Initially, the drive resonates with, and phase-locks to, a group of axially bouncing electrons in the trap. These initially phase-locked electrons remain phase-locked (in "autoresonance") during a subsequent downward chirp of the external potential's oscillation frequency. Only a few new particles are added to the resonant group as the frequency, and, hence, the resonance, moves to lower velocities in phase space. Consequently, the downward chirp creates a charge density perturbation (a hole) in the electron phase space distribution. The hole oscillates in space, and its associated induced electric field constitutes a BGK mode synchronized with the drive. The size of the hole in phase space, and thus the amplitude of the mode, are largely controlled by only two external parameters: the driving frequency and amplitude. A simplified kinetic theory of this excitation process is developed. The dependence of the excited BGK mode amplitude on the driving frequency chirp rate and other plasma parameters is discussed and theoretical predictions are compared with recent experiments and computer simulations.
    BibTeX:
    @article{friedland:4305,
      author = {L. Friedland and F. Peinetti and W. Bertsche and J. Fajans and J. S. Wurtele},
      title = {Driven phase space holes and synchronized Bernstein, Greene, and Kruskal modes},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2004},
      volume = {11},
      number = {9},
      pages = {4305-4317},
      url = {http://link.aip.org/link/?PHP/11/4305/1},
      doi = {http://dx.doi.org/10.1063/1.1781166}
    }
    					
    A. Friedman, J. J. Barnard, D. P. Grote, D. A. Callahan, G. J. Caporaso, R. J. Briggs, C. M. Celata, A. Faltens, E. Henestroza, I. Kaganovich, E. P. Lee, M. Leitner, B. G. Logan, L. R. Reginato, W. Waldron, S. S. Yu, R. C. Davidson, L. Grisham, R. W. Lee, S. D. Nelson, M. Tabak, C. L. Olson, G. Penn, A. Sessler, J. W. Staples, J. S. Wurtele, T. Renk, D. Rose, C. Thoma & D. R. Welch Highly Compressed Ion Beams for High Energy Density Science 2005 Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the, pp. 339-343  
    Abstract: The Heavy Ion Fusion Virtual National Laboratory is developing the intense ion beams needed to drive matter to the High Energy Density regimes required for Inertial Fusion Energy and other applications. An interim goal is a facility for Warm Dense Matter studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target ``foils,'' which may in fact be foams with mean densities 1% to 10% of solid. This approach complements that being pursued at GSI Darmstadt, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrical target. We present the beam requirements for Warm Dense Matter experiments. We discuss neutralized drift compression and final focus experiments and modeling. We describe suitable accelerator architectures based on Drift-Tube Linac, RF, single-gap, Ionization-Front Accelerator, and Pulse-Line Ion Accelerator concepts. The last of these is being pursued experimentally. Finally, we discuss plans toward a user facility for target experiments.
    BibTeX:
    @article{1590428,
      author = {Friedman, A. and Barnard, J. J. and Grote, D. P. and Callahan, D. A. and Caporaso, G. J. and Briggs, R. J. and Celata, C. M. and Faltens, A. and Henestroza, E. and Kaganovich, I. and Lee, E. P. and Leitner, M. and Logan, B. G. and Reginato, L. R. and Waldron, W. and Yu, S. S. and Davidson, R. C. and Grisham, L. and Lee, R. W. and Nelson, S. D. and Tabak, M. and Olson, C. L. and Penn, G. and Sessler, A. and Staples, J. W. and Wurtele, J. S. and Renk, T. and Rose, D. and Thoma, C. and Welch, D. R.},
      title = {Highly Compressed Ion Beams for High Energy Density Science},
      journal = {Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the},
      year = {2005},
      pages = {339-343}
    }
    					
    M. Fujiwara, G. Andresen, W. Bertsche, A. Boston, P. Bowe, C. Cesar, S. Chapman, M. Charlton, M. Chartier, A. Deutsch, J. Fajans, R. Funakoshi, D. Gill, K. Gomberoff, J. Hangst, W. Hardy, R. Hayano, R. Hydomako, M. Jenkins, L. Jørgensen, L. Kurchaninov, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. Page, A. Povilus, F. Robicheaux, E. Sarid, D. Silveira, J. Storey, R. Thompson, D. van der Werf, J. S. Wurtele, Y. Yamazaki & A. Collaboration Towards antihydrogen confinement with the ALPHA antihydrogen trap 2006 Hyperfine Interactions
    Vol. 172 (1), pp. 81-89  
    Abstract: ALPHA is an international project that has recently begun experimentation at CERN's Antiproton Decelerator (AD) facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms with the ultimate goal of precise spectroscopic comparisons with hydrogen. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.
    BibTeX:
    @article{Fujiwara:2006rb,
      author = {Fujiwara, M. and Andresen, G. and Bertsche, W. and Boston, A. and Bowe, P. and Cesar, C. and Chapman, S. and Charlton, M. and Chartier, M. and Deutsch, A. and Fajans, J. and Funakoshi, R. and Gill, D. and Gomberoff, K. and Hangst, J. and Hardy, W. and Hayano, R. and Hydomako, R. and Jenkins, M. and Jørgensen, L. and Kurchaninov, L. and Madsen, N. and Nolan, P. and Olchanski, K. and Olin, A. and Page, R. and Povilus, A. and Robicheaux, F. and Sarid, E. and Silveira, D. and Storey, J. and Thompson, R. and van der Werf, D. and Wurtele, J. S. and Yamazaki, Y. and , and ALPHA Collaboration},
      title = {Towards antihydrogen confinement with the ALPHA antihydrogen trap},
      journal = {Hyperfine Interactions},
      year = {2006},
      volume = {172},
      number = {1},
      pages = {81--89},
      url = {http://dx.doi.org/10.1007/s10751-007-9527-2}
    }
    					
    M. C. Fujiwara, G. B. Andresen, W. Bertsche, P. D. Bowe, C. C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, R. Funakoshi, D. R. Gill, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, M. J. Jenkins, L. V. J. rgensen, L. Kurchaninov, W. Lai, R. Lambo, N. Madsen, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, L. Wasilenko, J. S. Wurtele & Y. Yamazaki Y. Kanai & Y. Yamazaki (Hrsg.) Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN 2008 Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics
    Vol. 1037 (1), pp. 208-220  
    Abstract: We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.
    BibTeX:
    @conference{fujiwara:208,
      author = {M. C. Fujiwara and G. B. Andresen and W. Bertsche and P. D. Bowe and C. C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and R. Funakoshi and D. R. Gill and J. S. Hangst and W. N. Hardy and R. S. Hayano and M. E. Hayden and A. J. Humphries and R. Hydomako and M. J. Jenkins and L. V. Jø rgensen and L. Kurchaninov and W. Lai and R. Lambo and N. Madsen and P. Nolan and K. Olchanski and A. Olin and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and L. Wasilenko and J. S. Wurtele and Y. Yamazaki},
      title = {Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN},
      journal = {Proceedings of the Workshop on Cold Antimatter Plasmas and Applications to Fundamental Physics},
      publisher = {AIP},
      year = {2008},
      volume = {1037},
      number = {1},
      pages = {208-220},
      url = {http://link.aip.org/link/?APC/1037/208/1},
      doi = {http://dx.doi.org/10.1063/1.2977840}
    }
    					
    G. Penn, A. M. Sessler & J. S. Wurtele A plasma channel beam conditioner 2007 (TUPMN113)  
    Abstract: By "conditioning" an electron beam, through establishing a correlation between transverse action and energy within the beam, the performance of free electron lasers (FELs) can be dramatically improved. Under certain conditions, the FEL can perform as if the transverse emittances of the beam were substantially lower than the actual values. After a brief review of the benefits of beam conditioning, we present a method to generate this correlation through the use of a plasma channel. The strong transverse focusing produced by a plasma channel (chosen to have density 1016 /cm3 ) allows the optimal correlation to be achieved in a reasonable length channel, of order 1 m. This appears to be a convenient and practical method for achieving conditioned beams, in comparison with other methods which require either a long beamline or multiple passes through some type of ring.
    BibTeX:
    @conference{Penn:TUPMN113,
      author = {G. Penn, and A. M. Sessler, and J. S. Wurtele},
      title = {A plasma channel beam conditioner},
      year = {2007},
      number = {TUPMN113},
      note = {Proceedings of PAC07, Albuquerque, New Mexico, USA}
    }
    					
    G. Penn, J. S Wurtele & W. M. Fawley Helical Channels for Longitudinal Compression of Muon Beams 2001 (FPAH092)  
    Abstract: Traverse cooling of muon beams can be achieved through ionization cooling. However, longitudinal emittance growth occurs as a by-product of this method; at the muon energy of choice, low energy muons suffer enhanced energy loss. Even a small amount of longitudinal cooling would be advantageous for a neutino factory, while longitudinal cooling by a factor of 100 is required for a muon collider. We consider 6D cooling useing a helical wiggler channel inside a uniform solenoid field, which results in radial dispersion, which is combined with wedge-shaped absorbers to correct the energy spread and transfer longitudinal emittance into the tranverse defrees of freedom. These systems are challenging because of the large dispersions required, and abecause the muon beams have large energy spread and non-zero transverse emittance. We describe scenarios which, in simulations, yield significant reduction of energy spread for unbunched beams. We explore the demands and performance of such channels, as well as the feasibility of longitudinal compression for bunched beams.
    BibTeX:
    @conference{Penn:FPAH092,
      author = {G. Penn, and J. S Wurtele, and W. M. Fawley},
      title = {Helical Channels for Longitudinal Compression of Muon Beams},
      year = {2001},
      number = {FPAH092},
      note = {Proceedings of 2001 Particle Accelerator Conference, Chicago}
    }
    					
    G. Penn, M. Reinsch, J. S. Wurtele, J. N. Corlett, W. M. Fawley, A. Zholents & W. Wan Harmonic Cascade FEL Designs for LUX 2004 (MOPKF074)  
    Abstract: LUX is a design concept for an ultrafast X-ray science facility, based on an electron beam accelerated to GeV energies in a recirculating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 200≠250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam
    BibTeX:
    @conference{Penn:MOPKF074,
      author = {G. Penn, and M. Reinsch, and J. S. Wurtele , and J. N. Corlett, and W. M. Fawley, and A. Zholents, and W. Wan},
      title = {Harmonic Cascade FEL Designs for LUX},
      year = {2004},
      number = {MOPKF074},
      note = {Proceedings of EPAC 2004, Lucerne, Switzerland}
    }
    					
    G. Penn, M. Reinsch & J. S. Wurtele Analytic Model of Harmonic Generation in the Low-Gain FEL Regime 2004 (MOPOS57)  
    Abstract: Harmonic generation using free electron lasers (FELs) requires two undulators: the first uses a seed laser to modulate the energy of the electron beam; the second undulator uses the subsequently bunched beam to radiate at a higher harmonic. These processes are currently evaluated using extensive calculations or simulation codes which can be slow to evaluate and difficult to set up. We describe a simple algorithm to predict the output of a harmonic generation beamline in the low-gain regime based on trial functions for the output radiation. Full three-dimensional effects are included. This method has been implemented as a Mathematica script which runs rapidly and can be generalized to include effects such as asymmetric beams and misalignments. This method is compared with simulation results using the FEL code GENESIS, both for single stages of harmonic generation and for the LUX project, a design concept for an ultrafast X-ray facility, where multiple stages upshift the input laser frequency by factors of up to 200.
    BibTeX:
    @conference{Penn:MOPOS57,
      author = {G. Penn, and M. Reinsch, and J. S. Wurtele},
      title = {Analytic Model of Harmonic Generation in the Low-Gain FEL Regime},
      year = {2004},
      number = {MOPOS57},
      note = {Proceedings of the 2004 FEL Conference}
    }
    					
    G. Penn & J. S. Wurtele Simulation of the Ionization Cooling of Muons in Linear RF Systems 2000 (TH203)  
    Abstract: Ionization cooling of muon beams is a crucial component of the proposed muon collider and neutrino factory. Current studies of cooling channels predominatly use simulations which track single particles, an often time consuming procedure. These simulaton efforts are discussed and compared with analytic studies using equations for the beam moments in a linear channel. These dynamic equations, which analogous to the Courant-Snyder description of quadrupole focussing, incorporate the basic aspects of ionization cooling: energy loss and scattering in material, acceleration by radio frequency (RF) cavities, and focussing in solenoid magnets. This formalism can be used to study a wide range of cooling channels, and to evaluate the impact of engineering constraints on cooling channel performance.
    BibTeX:
    @conference{Penn:TH203,
      author = {G. Penn, and J. S. Wurtele},
      title = {Simulation of the Ionization Cooling of Muons in Linear RF Systems},
      year = {2000},
      number = {TH203},
      note = {Contributed to XX International Linac Accelerator Conference (LINAC 00), Monterey, California, 21-25 August 2000}
    }
    					
    K. Gomberoff, J. Fajans, A. Friedman, D. Grote, J.-L. Vay & J. S. Wurtele Simulations of plasma confinement in an antihydrogen trap 2007 Phys. of Plasma
    Vol. 14 (10), pp. 102111  
    Abstract: The three-dimensional particle-in-cell (3-D PIC) simulation code WARP is used to study positron confinement in antihydrogen traps. The magnetic geometry is close to that of a UC Berkeley experiment conducted, with electrons, as part of the ALPHA collaboration [W. Bertsche et al., AIP Conf. Proc. 796, 301 (2005)]. In order to trap antihydrogen atoms, multipole magnetic fields are added to a conventional Malmberg-Penning trap. These multipole fields must be strong enough to confine the antihydrogen, leading to multipole field strengths at the trap wall comparable to those of the axial magnetic field. Numerical simulations reported here confirm recent experimental measurements of reduced particle confinement when a quadrupole field is added to a Malmberg-Penning trap. It is shown that, for parameters relevant to various antihydrogen experiments, the use of an octupole field significantly reduces the positron losses seen with a quadrupole field. A unique method for obtaining a 3-D equilibrium of the positrons in the trap with a collisionless PIC code was developed especially for the study of the antihydrogen trap; however, it is of practical use for other traps as well
    BibTeX:
    @article{gomberoff:102111,
      author = {K. Gomberoff and J. Fajans and A. Friedman and D. Grote and J.-L. Vay and J. S. Wurtele},
      title = {Simulations of plasma confinement in an antihydrogen trap},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2007},
      volume = {14},
      number = {10},
      pages = {102111},
      url = {http://link.aip.org/link/?PHP/14/102111/1},
      doi = {http://dx.doi.org/10.1063/1.2778420}
    }
    					
    K. Gomberoff, J. Fajans, J. S. Wurtele, A. Friedman, D. P. Grote, R. H. Cohen & J. L. Vay Simulation studies of non-neutral plasma equilibria in an electrostatic trap with a magnetic mirror 2007 Phys. of Plasma
    Vol. 14 (5), pp. 052107  
    Abstract: The equilibrium of an infinitely long, strongly magnetized, non-neutral plasma confined in a Penning-Malmberg trap with an additional mirror coil has been solved analytically [J. Fajans, Phys. Plasmas 10, 1209 (2003)] and shown to exhibit unusual features. Particles not only reflect near the mirror in the low field region, but also may be weakly trapped in part of the high field region. The plasma satisfies a Boltzmann distribution along field lines; however, the density and the potential vary along field lines. Some other simplifying assumptions were employed in order to analytically characterize the equilibrium; for example the interface region between the low and high field regions was not considered. The earlier results are confirmed in the present study, where two-dimensional particle-in-cell (PIC) simulations are performed with the Warp code in a more realistic configuration with an arbitrary (but physical) density profile, realistic trap geometry and magnetic field. A range of temperatures and radial plasma sizes are considered. Particle tracking is used to identify populations of trapped and untrapped particles. The present study also shows that it is possible to obtain local equilibria of non-neutral plasmas using a collisionless PIC code, by a scheme that uses the inherent numerical collisionality as a proxy for physical collisions.
    BibTeX:
    @article{gomberoff:052107,
      author = {K. Gomberoff and J. Fajans and J. S. Wurtele and A. Friedman and D. P. Grote and R. H. Cohen and J. L. Vay},
      title = {Simulation studies of non-neutral plasma equilibria in an electrostatic trap with a magnetic mirror},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2007},
      volume = {14},
      number = {5},
      pages = {052107},
      url = {http://link.aip.org/link/?PHP/14/052107/1},
      doi = {http://dx.doi.org/10.1063/1.2727470}
    }
    					
    K. Gomberoff, J. S. Wurtele, A. Friedman, D. P. Grote & J. L. Vay A method for obtaining three-dimensional computational equilibrium of non-neutral plasmas using WARP 2007 Journal of Computational Physics
    Vol. 225 (2), pp. 1736 - 1752  
    Abstract: Computer simulation studies of the stability and transport properties of trapped non-neutral plasmas require the numerical realization of a three-dimensional plasma distribution. This paper presents a new numerical method for obtaining, without an explicit model for physical collisions in the code, a low noise three-dimensional computational equilibrium distribution. This requires both the loading of particles into an idealized distribution and the relaxation from that distribution toward an approximate numerical equilibrium. The equilibrium can then be modified through a slow change of system parameters, to generate other equilibria. In the present, work we apply this method to a UC Berkeley experiment on electron confinement in magnetic geometries appropriate for the ALPHA anti-hydrogen experiment, using the three-dimensional particle-in-cell code WARP. WARP's guiding center mover and its option to switch between different solvers during a simulation are highly valuable because they speed up the simulations; they enable the practical use of the new technique for generating numerical equilibrium states of trapped non-neutral plasmas.
    BibTeX:
    @article{Gomberoff20071736,
      author = {K. Gomberoff and J. S. Wurtele and A. Friedman and D. P. Grote and J. L. Vay},
      title = {A method for obtaining three-dimensional computational equilibrium of non-neutral plasmas using WARP},
      journal = {Journal of Computational Physics},
      year = {2007},
      volume = {225},
      number = {2},
      pages = {1736 - 1752},
      url = {http://www.sciencedirect.com/science/article/B6WHY-4N85BD5-1/2/bc0ba259790de0678b9acb2378cb8840},
      doi = {DOI: 10.1016/j.jcp.2007.02.029}
    }
    					
    V. V. Gorgadze, L. Friedland & J. S. Wurtele Autoresonant control of a pre-excited diocotron mode 2007 Phys. of Plasma
    Vol. 14 (8), pp. 082317  
    Abstract: A new method for the manipulation of a pre-excited l = 1 diocotron mode in a pure electron plasma in a Malmberg-Penning trap is proposed and analyzed. The plasma is passively coupled to an external oscillatory circuit with slowly varying parameters. A threshold on the coupling strength is derived beyond which the plasma is continuously self-phase-locked to the external circuit. In the case of a linearly chirped circuit frequency, this autoresonant plasma can be driven to the wall, and in the case of a chirped sinusoidal variation of the circuit frequency, the plasma can be driven to the center of the trap. Derived thresholds on the coupling strength are in good agreement with simulations. Unlike conventional feedback mechanisms, autoresonant phase locking is a consequence of the nonlinearity of the system.
    BibTeX:
    @article{gorgadze:082317,
      author = {V. V. Gorgadze and L. Friedland and J. S. Wurtele},
      title = {Autoresonant control of a pre-excited diocotron mode},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2007},
      volume = {14},
      number = {8},
      pages = {082317},
      url = {http://link.aip.org/link/?PHP/14/082317/1},
      doi = {http://dx.doi.org/10.1063/1.2762131}
    }
    					
    V. V. Gorgadze & J. S. Wurtele Space-charge effects near a cathode 2005 (TPPE064)  
    Abstract: RF photocathode guns are excellent sources of high brightness electron bunches. To mitigate space charge effects downstream of the gun it is often desirable to produce electron bunches with a uniform density distribution. Our goal is to understand how the longitudinal bunch profile is determined by the emission dictated by the laser pulse intensity and the effects of the self-field dynamics near the cathode. The particle-in-cell simulation XOOPIC is used to simulate beam dynamics near the cathode and the results are compared to those obtained from linear theory. Studies are focused on flat-top and Gaussian bunch profiles.
    BibTeX:
    @conference{Gorgadze:TPPE064,
      author = {V. V. Gorgadze and J. S. Wurtele},
      title = {Space-charge effects near a cathode},
      year = {2005},
      number = {TPPE064},
      note = {Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee}
    }
    					
    R. Govil, W. P. Leemans, E. Y. Backhaus & J. S. Wurtele Observation of Return Current Effects in a Passive Plasma Lens 1999 Phys. Rev. Lett.
    Vol. 83 (16), pp. 3202-3205  
    Abstract: Observations of relativistic beam focusing by a passive plasma lens have demonstrated a reduction in focusing strength due to plasma return current. A 50 MeV beam was propagated through a 1--3 cm long plasma with density around 1014 cm-3. Beam size was measured as a function of propagation distance. For a ratio of collisionless plasma skin depth to beam spot size kpσr = 0.33, no significant reduction in focusing was observed. Reduced focusing was measured for kpσr = 1.1, where a significant fraction of the inductively driven return current in the plasma flows within the beam. The observations are in good agreement with an envelope equation model and with particle-in-cell simulations.
    BibTeX:
    @article{PhysRevLett.83.3202,
      author = {Govil, R. and Leemans, W. P. and Backhaus, E. Yu. and Wurtele, J. S.},
      title = {Observation of Return Current Effects in a Passive Plasma Lens},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1999},
      volume = {83},
      number = {16},
      pages = {3202--3205},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.83.3202}
    }
    					
    M. E. Griswold, N. J. Fisch & J. S. Wurtele An upper bound to time-averaged space-charge limited diode currents 2010 Physics of Plasmas
    Vol. 17 (11), pp. 114503  
    Abstract: The Child?Langmuir law limits the steady-state current density across a one-dimensional planar diode. While it is known that the peak current density can surpass this limit when the boundary conditions vary in time, it remains an open question of whether the average current can violate the Child?Langmuir limit under time-dependent conditions. For the case where the applied voltage is constant but the electric field at the cathode is allowed to vary in time, one-dimensional particle-in-cell simulations suggest that such a violation is impossible. Although a formal proof is not given, an upper bound on the time-averaged current density is offered.
    BibTeX:
    @article{Griswold2010,
      author = {M. E. Griswold and N. J. Fisch and J. S. Wurtele},
      title = {An upper bound to time-averaged space-charge limited diode currents},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2010},
      volume = {17},
      number = {11},
      pages = {114503},
      url = {http://link.aip.org/link/?PHP/17/114503/1},
      doi = {http://dx.doi.org/10.1063/1.3503661}
    }
    					
    N. Z. D. Group & N. P. W. G. S. Kuhlman Physics and Technology of the Next Linear Collider: A Report Submitted to Snowmass '96 1996 (9605011)  
    Abstract: We present the current expectations for the design and physics program of an e+e- linear collider of center of mass energy 500 GeV -- 1 TeV. We review the experiments that would be carried out at this facility and demonstrate its key role in exploring physics beyond the Standard Model over the full range of theoretical possibilities. We then show the feasibility of constructing this machine, by reviewing the current status of linear collider technology and by presenting a precis of our `zeroth-order' design.
    BibTeX:
    @misc{group-1996,
      author = {NLC ZDR Design Group and NLC Physics Working Groups: S. Kuhlman},
      title = {Physics and Technology of the Next Linear Collider: A Report Submitted to Snowmass '96},
      year = {1996},
      number = {9605011},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:hep-ex/9605011}
    }
    					
    M. Gullans, G. Penn, J. S. Wurtele & M. Zolotorev Three-dimensional analysis of free-electron laser performance using brightness scaled variables 2008 Phys. Rev. ST Accel. Beams
    Vol. 11 (6), pp. 060701  
    Abstract: A three-dimensional analysis of radiation generation in a free-electron laser (FEL) is performed in the small signal regime. The analysis includes beam conditioning, harmonic generation, flat beams, and a new scaling of the FEL equations using the six-dimensional beam brightness. The six-dimensional beam brightness is an invariant under Liouvillian flow; therefore, any nondissipative manipulation of the phase space, performed, for example, in order to optimize FEL performance, must conserve this brightness. This scaling is more natural than the commonly used scaling with the one-dimensional growth rate. The brightness-scaled equations allow for the succinct characterization of the optimal FEL performance under various additional constraints. The analysis allows for the simple evaluation of gain enhancement schemes based on beam phase space manipulations such as emittance exchange and conditioning. An example comparing the gain in the first and third harmonics of round or flat and conditioned or unconditioned beams is presented.
    BibTeX:
    @article{PhysRevSTAB.11.060701,
      author = {Gullans, M. and Penn, G. and Wurtele, J. S. and Zolotorev, M.},
      title = {Three-dimensional analysis of free-electron laser performance using brightness scaled variables},
      journal = {Phys. Rev. ST Accel. Beams},
      publisher = {American Physical Society},
      year = {2008},
      volume = {11},
      number = {6},
      pages = {060701},
      doi = {http://dx.doi.org/10.1103/PhysRevSTAB.11.060701}
    }
    					
    M. Gullans, J. S. Wurtele, G. Penn & A. A. Zholents Performance study of a soft X-ray harmonic generation FEL seeded with an EUV laser pulse 2007 Optics Communications
    Vol. 274 (1), pp. 167-175  
    Abstract: The performance of a free electron laser (FEL) using a low-power extreme ultraviolet (EUV) pulse as an input seed is investigated. The parameters are appropriate for 30†nm seeds produced from high-power Ti:Sapphire pulses using high harmonic generation schemes. It is found that, for reasonable beam parameters, robust FEL performance can be obtained. Both time-independent and time-dependent simulations are performed for varying system parameters using the GENESIS simulation code. A comparison is made with a two-stage harmonic FEL that is seeded by a high-power Ti:Sapphire pulse.
    BibTeX:
    @article{Gullans:2007zp,
      author = {Gullans, M. and Wurtele, J. S. and Penn, G. and Zholents, A. A.},
      title = {Performance study of a soft X-ray harmonic generation FEL seeded with an EUV laser pulse},
      journal = {Optics Communications},
      year = {2007},
      volume = {274},
      number = {1},
      pages = {167--175},
      url = {http://www.sciencedirect.com/science/article/B6TVF-4N56NS4-4/1/831b8447a699de1eda6a9c916f5ad0aa}
    }
    					
    F. Hartemann, K. Xu, G. Bekefi, J. S. Wurtele & J. Fajans Wave profile modification (optical guiding) induced by free-electron laser interaction 1987 Phys. Rev. Lett.
    Vol. 59 (11), pp. 1177-1180  
    Abstract: Modification of the transverse intensity profile of a single electromagnetic waveguide mode during the free-electron laser (FEL) interaction has been measured. This effect is the waveguide analog to free-space optical guiding. The studies were carried out at microwave frequencies (8--12 GHz) in a FEL with use of a mildly relativistic electron beam of ≃200 kV energy and ≃1.0 A current. The probing of the rf fields was accomplished by small electric dipole antennas inserted in the interaction region. The observed intensity profiles are compared with the measured FEL-induced phase shifts (wave refractive index).
    BibTeX:
    @article{PhysRevLett.59.1177,
      author = {Hartemann, F. and Xu, K. and Bekefi, G. and Wurtele, J. S. and Fajans, J.},
      title = {Wave profile modification (optical guiding) induced by free-electron laser interaction},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1987},
      volume = {59},
      number = {11},
      pages = {1177--1180},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.59.1177}
    }
    					
    J. L. Hsu, T. Katsouleas, W. B. Mori, C. B. Schroeder & J. S. Wurtele Laser acceleration in vacuum 1997 Particle Accelerator Conference, 1997. Proceedings of the 1997
    Vol. 1, pp. 684-686  
    Abstract: This paper explores the use of the large electric fields of high-brightness lasers (e.g., up to order TV/cm) to accelerate particles. Unfortunately, as is well known, it is difficult to couple the vacuum field of the laser to particles so as to achieve a net energy gain. In principle, the energy gain near the focus of the laser can be quite high, i.e., on the order of the work done in crossing the focus Δγ=√πeEw ~30 MeV√(P/1 TW), where P is the laser power. In order to retain this energy, the particles must be in the highly nonlinear regime (Vosc/c&Gt;1) or must be separated from the laser within a distance on the order of a Rayleigh length from the focus. In this work, we explore the acceleration and output energy distribution of an electron beam injected at various angles and injection energies into a focused laser beam. Insight into the physical mechanism of energy gain is obtained by separating the contributions from the longitudinal and transverse laser field components
    BibTeX:
    @article{749805,
      author = {Hsu, J. L. and Katsouleas, T. and Mori, W. B. and Schroeder, C. B. and Wurtele, J. S.},
      title = {Laser acceleration in vacuum},
      journal = {Particle Accelerator Conference, 1997. Proceedings of the 1997},
      year = {1997},
      volume = {1},
      pages = {684-686},
      doi = {http://dx.doi.org/10.1109/PAC.1997.749805}
    }
    					
    M. S. Hur, G. Penn, J. S. Wurtele & R. Lindberg Slowly varying envelope kinetic simulations of pulse amplification by Raman backscattering 2004 Phys. of Plasma
    Vol. 11 (11), pp. 5204-5211  
    Abstract: A numerical code based on an eikonal formalism has been developed to simulate laser-plasma interactions, specifically Raman backscatter (RBS). In this code, the dominant laser modes are described by their wave envelopes, avoiding the need to resolve the laser frequency; appropriately time-averaged equations describe particle motion. The code is fully kinetic, and thus includes critical physics such as particle trapping and Landau damping which are beyond the scope of the commonly used fluid three-wave equations. The dominant forces on the particles are included: the ponderomotive force resulting from the beat wave of the forward and backscattered laser fields and the self-consistent plasma electric field. The code agrees well, in the appropriate regimes, with the results from three-wave equations and particle-in-cell simulations. The effects of plasma temperature on RBS amplification are studied. It is found that increasing the plasma temperature results in modification to particle trapping and the saturation of RBS, even before the onset of Landau damping of the plasma wave. This results in a reduction in the coupling efficiency compared to predictions based on the three-wave equations.
    BibTeX:
    @article{hur:5204,
      author = {Min Sup Hur and Gregory Penn and Jonathan S. Wurtele and Ryan Lindberg},
      title = {Slowly varying envelope kinetic simulations of pulse amplification by Raman backscattering},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2004},
      volume = {11},
      number = {11},
      pages = {5204-5211},
      url = {http://link.aip.org/link/?PHP/11/5204/1},
      doi = {http://dx.doi.org/10.1063/1.1796351}
    }
    					
    M. S. Hur & J. S. Wurtele Two-dimensional simulations of the amplification and focusing of intense laser pulses in the kinetic regime of Raman backward amplification in plasmas 2009 Computer Physics Communications
    Vol. 180 (4), pp. 651 - 655  
    Abstract: Focusing of an intense laser pulse produced by backward Raman pulse amplification (BRA) has been numerically studied using a two-dimensional, axisymmetric kinetic model. The two-dimensional averaged particle-in-cell (aPIC) simulation assumes slowly varying field envelopes and is comprised of one-dimensional sub-models that are coupled radially through laser diffraction. A converging 33 TW seed pulse was amplified up to 1 PW. The focusing of the seed pulse, even when particle trapping was important, was maintained. It was also found that the focusing properties of the pulse tail can lead to some rewidening of the longitudinal pulse duration and some ideas for eliminating this effect were suggested. Simulations performed for various plasma densities and temperatures exhibited robust amplification and pulse shortening.
    BibTeX:
    @article{Hur2009651,
      author = {Min Sup Hur and Jonathan S. Wurtele},
      title = {Two-dimensional simulations of the amplification and focusing of intense laser pulses in the kinetic regime of Raman backward amplification in plasmas},
      journal = {Computer Physics Communications},
      year = {2009},
      volume = {180},
      number = {4},
      pages = {651 - 655},
      note = {Special issue based on the Conference on Computational Physics 2008 - CCP 2008},
      url = {http://www.sciencedirect.com/science/article/B6TJ5-4VF56Y0-2/2/3c1134f0d2bbb1e9ae70edd37858b815},
      doi = {DOI: 10.1016/j.cpc.2009.01.013}
    }
    					
    M. S. Hur, J. S. Wurtele & G. Penn Guiding of an electromagnetic pulse in a plasma immersed in combined wiggler and axial magnetic fields 2008 Phys. Rev. A
    Vol. 372 (19), pp. 3452 - 3455  
    Abstract: We present a new plasma-based method of guiding an electromagnetic pulse. The scheme consists of an inhomogeneous magnetic field and a uniform density plasma, in contrast to existing schemes that rely on transverse plasma density gradients but need not be magnetized. The refractive index of a magnetized plasma depends on the strength and direction of the magnetic field as well as the plasma density. A guiding channel is formed by using field inhomogeneity to generate the desired transverse profile of the index of refraction. The concept is analyzed with an envelope equation and, for the specific example of a wiggler magnetic field, with a two-dimension particle-in-cell simulation. A simplified model of this scheme as producing a magnetic wall in analogy to metallic waveguides is presented, for which corresponding approximate relations for the guided mode axial wavelength and radius are derived as functions of the plasma and magnetic field parameter. These are seen to be in good agreement with particle-in-cell simulation results. Since the desired inhomogeneity of the refractive index can be made easily when the electromagnetic wave frequency is close to the cyclotron frequency, this guiding scheme is most readily applied in the microwave regime.
    BibTeX:
    @article{Hur20083452,
      author = {Min Sup Hur and Jonathan S. Wurtele and Gregory Penn},
      title = {Guiding of an electromagnetic pulse in a plasma immersed in combined wiggler and axial magnetic fields},
      journal = {Phys. Rev. A},
      year = {2008},
      volume = {372},
      number = {19},
      pages = {3452 - 3455},
      url = {http://www.sciencedirect.com/science/article/B6TVM-4RDR18N-4/2/7f3b590ba47930e51cd8b5aefee5ee61},
      doi = {DOI: 10.1016/j.physleta.2007.12.024}
    }
    					
    M. S. Hur, J. S. Wurtele & G. Shvets Simulation of electromagnetically and magnetically induced transparency in a magnetized plasma 2003 Phys. of Plasma
    Vol. 10 (7), pp. 3004-3011  
    Abstract: Electromagnetically induced transparency (EIT), a phenomenon well known in atomic systems, has a natural analogy in a classical magnetized plasma. The magnetized plasma has a resonance for right-hand polarized electromagnetic waves at the electron cyclotron frequency Omega0, so that a probe wave with frequency omega1 = Omega0 cannot propagate through the plasma. The plasma can be made transparent to such a probe by the presence of a pump wave. The pump may be an electromagnetic wave or magnetostatic wiggler. Simulations and theory show that the physical reason for the transparency is that the beating of the probe wave with the pump wave sets up a plasma oscillation, and the upper sideband of the pump wave cancels the resonant plasma current due to the probe. The theory of plasma EIT derived here extends that found in the earlier work to include the effects of the lower sideband of the pump and renormalization of the plasma frequency and an analysis of the transient response. A detailed comparison of theory to one-dimensional particle-in-cell simulations is presented and estimates for the performance ion accelerator using the EIT interaction are given. The dispersion relation and estimates for the phase velocity and amplitude of the plasma wave are in good agreement with particle-in-cell simulations.
    BibTeX:
    @article{hur:3004,
      author = {M. S. Hur and J. S. Wurtele and G. Shvets},
      title = {Simulation of electromagnetically and magnetically induced transparency in a magnetized plasma},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2003},
      volume = {10},
      number = {7},
      pages = {3004-3011},
      url = {http://link.aip.org/link/?PHP/10/3004/1},
      doi = {http://dx.doi.org/10.1063/1.1580816}
    }
    					
    M. S. Hur, J. S. Wurtele & G. Shvets Magnetically Induced Transparency and Its Application as an Accelerator 2002 ADVANCED ACCELERATOR CONCEPTS: Tenth Workshop
    Vol. 647 (1), pp. 802-809  
    Abstract: Recently it was found [1--3] that a magnetized plasma can be made transparent to a right-hand polarized cyclotron frequency resonant wave in the presence of a strong pump or a helical magnetic wiggler. Theory predicts and simulations verify that the group velocity of the probe is slow, and the phase velocity of the longitudinal wave controllable. These properties of the system suggest the possibility of its being used as an advanced accelerator of heavy particles. We present the theory and simulations of transparency and a preliminary study of its application as an accelerator.
    BibTeX:
    @conference{hur:802,
      author = {M. S. Hur and J. S. Wurtele and G. Shvets},
      title = {Magnetically Induced Transparency and Its Application as an Accelerator},
      journal = {ADVANCED ACCELERATOR CONCEPTS: Tenth Workshop},
      publisher = {AIP},
      year = {2002},
      volume = {647},
      number = {1},
      pages = {802-809},
      url = {http://link.aip.org/link/?APC/647/802/1},
      doi = {http://dx.doi.org/10.1063/1.1524935}
    }
    					
    S. Ishii, G. Shvets & J. S. Wurtele Computationally efficient spectral analysis of an FEL oscillator using a Green function analysis 1995 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 358 (1-3), pp. 489-492  
    Abstract: Previous work on a Green function approach to the evolution of the small gain linear FEL oscillator assumed a long electron pulse. Here this restriction is eliminated and a new expression for the complex amplitude of the optical field at the nth pass is obtained. The fully causal formalism includes arbitrary temporal profiles of the electron and optical beams and cavity detuning and losses. In our formalism, the solution for the field at the nth pass requires exponentiating a single matrix rather than sequentially evaluating the field at each pass. Various numerical studies are presented.
    BibTeX:
    @article{Ishii:1995yq,
      author = {Ishii, S. and Shvets, G. and Wurtele, J. S.},
      title = {Computationally efficient spectral analysis of an FEL oscillator using a Green function analysis},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1995},
      volume = {358},
      number = {1-3},
      pages = {489--492},
      url = {http://www.sciencedirect.com/science/article/B6TJM-497C66C-4S/1/9c0584307c8c67f70be55ccac02a9889}
    }
    					
    J. Corlett, J. Byrd, W. M. Fawley, M. Gullans, D. Li, S. M. Lidia, H. Padmore, G. Penn, I. Pogorelov, J. Qiang, D. Robin, F. Sannibale, J. W. Staples, C. Steier, M. Venturini, S. Virostek, W. Wan, R. Wells, R. Wilcox, J. S. Wurtele & A. Zholents A high repetition rate vuv-soft x-ray fel concept 2007 (TUPMN109)  
    Abstract: We report on design studies for a seeded FEL light source that is responsive to the scientific needs of the future. The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, reduced gain length in the FEL, utilization of harmonics to attain shorter wavelengths, and precise synchronization of the x-ray pulse with seed laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FEL's, each producing high average brightness, tunable over the VUV≠soft x-ray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhanced-SASE (ESASE), seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands. relaxations in molecular systems and electron-lattice energy transfer times in crystalline solids. ∑ ~100 femtoseconds, characteristic of atomic vibrational periods in molecules and solids. ∑ ~10 femtoseconds, characteristic of electron-electron scattering times in solids. ∑ ~100 attoseconds, characteristic of electron-electron correlations and valence electron motion. The needs to directly probe electronic structure and dynamics demand a focus on the VUV and soft x-ray regions, and the creation of experimental facilities that complement those being constructed with hard x-ray capabilities.
    BibTeX:
    @conference{Corlett:TUPMN109,
      author = {J. Corlett, and J. Byrd, and W. M. Fawley, and M. Gullans, and D. Li, and S. M. Lidia, and H. Padmore, and G. Penn, and I. Pogorelov, and J. Qiang, and D. Robin, and F. Sannibale, and J. W. Staples, and C. Steier, and M. Venturini, and S. Virostek, and W. Wan, and R. Wells, and R. Wilcox, and J. S. Wurtele, and A. Zholents},
      title = {A high repetition rate vuv-soft x-ray fel concept},
      year = {2007},
      number = {TUPMN109}
    }
    					
    J. Corlett, W. Fawley, G. Penn, W. Wan & A. Zholents Harmonic Cascade FEL Designs for LUX, a Facilty for Ultrafast X-ray Science 2004 (THPOS51)  
    Abstract: LUX is a design study to develop concepts for future ultrafast x-ray facilities. Presently, LUX is based on an electron beam accelerated to 3-GeV energy in a superconducting, recirculating linac. Included in the design are multiple free-electron laser (FEL) beamlines which use the harmonic cascade approach to produce coherent XUV & soft X-ray emission beginning with a strong input seed at 200nm wavelength obtained from a "conventional" laser. Each cascade module generally operates in the low-gain regime and is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a "virgin" pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse. For a given cascade, the output photon energy can be selected over a wide range by varying the seed laser wavelength and the field strength in the undulators. We present numerical simulation results, as well as those from analytical models, to examine certain aspects of the predicted FEL performance. We also discuss lattice considerations pertinent to harmonic cascade FELs, somesensitivity studies and requirements on the undulator alignment, and temporal pulse evolution initiated by short input radiation seeds.
    BibTeX:
    @conference{Corlett:THPOS51,
      author = {J. Corlett, and W. Fawley, and G. Penn, and W. Wan, and A. Zholents},
      title = {Harmonic Cascade FEL Designs for LUX, a Facilty for Ultrafast X-ray Science},
      year = {2004},
      number = {THPOS51},
      note = {Proceedings of the 2004 FEL Conference}
    }
    					
    J. N. Corlett, W. A. Barletta, S. DeSantis, L. Doolittle, W. M. Fawley, P. Heimann, S. Leone, S. Lidia, D. Li, G. Penn, A. Ratti, M. Reinsch, R. Schoenlein, J. Staples, G. Stover, S. Virostek, W. Wan, R. Wells, R. Wilcox, A. Wolski, J. S. Wurtele & A. Zholents LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science 2004 (THPKF075)  
    BibTeX:
    @conference{Corlett:THPKF075,
      author = {J. N. Corlett, and W. A. Barletta, and S. DeSantis, and L. Doolittle, and W. M. Fawley, and P. Heimann, and S. Leone, and S. Lidia, and D. Li, and G. Penn, and A. Ratti, and M. Reinsch, and R. Schoenlein, and J. Staples, and G. Stover, and S. Virostek, and W. Wan, and R. Wells, and R. Wilcox, and A. Wolski, and J. S. Wurtele, and A. Zholents},
      title = {LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science},
      year = {2004},
      number = {THPKF075},
      note = {Proceedings of EPAC 2004, Lucerne, Switzerland}
    }
    					
    K. D. Jacobs, P. T. Demos, J. B. Flanz, A. Zolfaghari, J. S. Wurtele, X. T. Yu & K. Balewski Instability calculations for the MIT-Bates South Hall Ring 1991 Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE
    Vol. 3, pp. 1791-1793  
    Abstract: Instability growth rates and thresholds have been calculated for the MIT-Bates South Hall Ring. Both single bunch and coupled bunch instabilities have been investigated. For single bunch effects, a broadband impedance budget has been developed. Numerical estimates of the impedances of ring components were made, and required to be within the budget. As part of this, the difficulty of fitting computed loss parameters to those derived from the usual broadband impedance model were studied. The authors conclude single bunch instabilities should not be a problem. However, coupled bunch instabilities are a serious concern, since all 1812 of the 2856 MHz RF buckets around the ring are filled
    BibTeX:
    @article{164779,
      author = {Jacobs, K. D. and Demos, P. T. and Flanz, J. B. and Zolfaghari, A. and Wurtele, J. S. and Yu, X. T. and Balewski, K.},
      title = {Instability calculations for the MIT-Bates South Hall Ring},
      journal = {Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE},
      year = {1991},
      volume = {3},
      pages = {1791-1793},
      doi = {http://dx.doi.org/10.1109/PAC.1991.164779}
    }
    					
    E. Jerby, G. Bekefi & J. S. Wurtele Experimental and theoretical study of periodic intensity bursts in the start-up phase of a free-electron laser oscillator 1991 Quantum Electronics, IEEE Journal of
    Vol. 27 (12), pp. 2512-2521  
    Abstract: Experimental observations and a theoretical analysis of periodic radiation bursts and macropulse formation in the startup phase of a free-electron laser (FEL) oscillator are presented. This microwave FEL uses a long pulse electron beam with a slowly decaying voltage. The output radiation consists of a superposition of bell-shaped macropulses, each of which is composed of a periodic sequence of short micropulses. The micropulses are separated by a cavity round-trip time. Each bell-shaped macropulse has a random startup time and amplitude. The startup of the radiation macropulses is correlated with random current spikes on the continuous electron beam. The observed macropulse signal agrees with a theoretical calculation of the impulse response of the FEL oscillator when the shift in the FEL resonance frequency arising from the slow voltage drop of the electron beam is included in the analysis. Possible applications of the macropulse formation phenomena in the FEL are discussed
    BibTeX:
    @article{104127,
      author = {Jerby, E. and Bekefi, G. and Wurtele, J. S.},
      title = {Experimental and theoretical study of periodic intensity bursts in the start-up phase of a free-electron laser oscillator},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1991},
      volume = {27},
      number = {12},
      pages = {2512-2521},
      doi = {http://dx.doi.org/10.1109/3.104127}
    }
    					
    E. Jerby, G. Bekefi & J. S. Wurtele Observations of periodic intensity bursts during the start-up phase of a free-electron-laser oscillator 1991 Phys. Rev. Lett.
    Vol. 66 (16), pp. 2068-2071  
    Abstract: Observations of periodic intensity bursts during the start-up phase of a free-electron-laser oscillator operating in the microwave regime are reported. The bursts are composed of radiation micropulses several nanoseconds wide and separated by the resonant-cavity round-trip time (∼35 ns). The occurrence of the bursts is correlated to random current spikes superposed on the continuous electron-beam current density. The observations are compared with theoretical results from an impulse response model of a free-electron laser.
    BibTeX:
    @article{PhysRevLett.66.2068,
      author = {Jerby, E. and Bekefi, G. and Wurtele, J. S.},
      title = {Observations of periodic intensity bursts during the start-up phase of a free-electron-laser oscillator},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1991},
      volume = {66},
      number = {16},
      pages = {2068--2071},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.66.2068}
    }
    					
    L. V. Jørgensen, G. Andresen, W. Bertsche, A. Boston, P. D. Bowe, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, M. C. Fujiwara, R. Funakoshi, D. R. Gill, J. S. Hangst, R. S. Hayano, R. Hydomako, M. J. Jenkins, L. Kurchaninov, N. Madsen, P. Nolan, K. Olchanski, A. Olin, R. D. Page, A. Povilus, F. Robicheaux, E. Sarid, D. M. Silveira, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Towards trapped antihydrogen 2008 Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
    Vol. 266 (3), pp. 357 - 362  
    Abstract: Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN's Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.
    BibTeX:
    @article{Jorgensen2008357,
      author = {L. V. Jørgensen and G. Andresen and W. Bertsche and A. Boston and P. D. Bowe and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and M. C. Fujiwara and R. Funakoshi and D. R. Gill and J. S. Hangst and R. S. Hayano and R. Hydomako and M. J. Jenkins and L. Kurchaninov and N. Madsen and P. Nolan and K. Olchanski and A. Olin and R. D. Page and A. Povilus and F. Robicheaux and E. Sarid and D. M. Silveira and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki},
      title = {Towards trapped antihydrogen},
      journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
      year = {2008},
      volume = {266},
      number = {3},
      pages = {357 - 362},
      note = {Low Energy Positron and Positronium Physics - Proceedings of the XIV International Workshop on Low Energy Positron and Positronium Physics},
      url = {http://www.sciencedirect.com/science/article/B6TJN-4RC2RVC-8/2/b4a486b238cdafb3708649d16ca9769b},
      doi = {DOI: 10.1016/j.nimb.2007.12.009}
    }
    					
    T. Katsouleas, T. C. Chiou, W. B. Mori, J. S. Wurtele & G. Shvets Studies of intense laser propagation in channels for extended length plasma accelerators 1995 Particle Accelerator Conference, 1995., Proceedings of the 1995
    Vol. 2, pp. 773-775  
    Abstract: Progress on modeling plasma-based accelerator concepts in plasma channels is presented. Such schemes offer the potential for large accelerating gradients, high beam quality and acceleration over many Rayleigh lengths by optically guiding intense laser pulses. Recent results include modeling of non-ideal channels, higher order laser modes, and instabilities. Curiously we find that Raman scatter and laser hosing are to a large extent suppressed in a hollow channel
    BibTeX:
    @article{504787,
      author = {Katsouleas, T. and Chiou, T. C. and Mori, W. B. and Wurtele, J. S. and Shvets, G.},
      title = {Studies of intense laser propagation in channels for extended length plasma accelerators},
      journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995},
      year = {1995},
      volume = {2},
      pages = {773-775},
      doi = {http://dx.doi.org/10.1109/PAC.1995.504787}
    }
    					
    T. Katsouleas, W. B. Mori, C. Decker, T. C. Chiou, J. S. Wurtele & G. Shvets Recent work on short pulse laser-plasma accelerators 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 4, pp. 2635-2637  
    Abstract: Theory and simulation of short-pulse laser plasma accelerators is presented. The plasma beat wave and laser wakefield accelerators are examined for the parameters of recently developed high-brightness lasers. For typical parameters, energy gains of 0.3 to 1 GeV over a few centimeters length appear feasible with a short pulse beat wave design. Issues important for extending these designs to multi-GeV acceleration of beams with high beam quality are examined, including optical guiding of the lasers, non-linear laser and wake velocity shifts, and long-term stability of the laser pulses
    BibTeX:
    @article{309411,
      author = {Katsouleas, T. and Mori, W. B. and Decker, C. and Chiou, T. C. and Wurtele, J. S. and Shvets, G.},
      title = {Recent work on short pulse laser-plasma accelerators},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {4},
      pages = {2635-2637},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309411}
    }
    					
    Y. Kawai, H. Saito & J. S. Wurtele Competing instabilities in the circular free-electron laser 1991 Physics of Fluids B: Plasma Physics
    Vol. 3 (6), pp. 1485-1495  
    Abstract: A small signal theory of the circular free-electron laser (FEL) is developed. A matrix dispersion relation, which includes coupling between the transverse magnetic (TM) and transverse electric (TE) waveguide modes, is derived from a Eulerian fluid model. The full dispersion equation is then expanded around the TM and TE mode resonant frequencies of the circular coaxial waveguide. The growth rate for frequencies near the TM mode resonance agrees with previous results obtained from a nonlinear pendulum model of the circular FEL, and becomes the negative mass growth rate as the wiggler field strength approaches to zero. It is shown that the dispersion relation expanded near the TE mode resonance has a coupling with the wiggler field that is different from the usual FEL mechanism. In the limit of a weak wiggler field, the dispersion relation for frequencies near a TE resonance reduces to that of the cyclotron maser. Numerical calculations of the growth rate and the ratio of the amplitudes of TE and TM modes are presented.
    BibTeX:
    @article{kawai:1485,
      author = {Yasushi Kawai and Hirobumi Saito and Jonathan S. Wurtele},
      title = {Competing instabilities in the circular free-electron laser},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1991},
      volume = {3},
      number = {6},
      pages = {1485-1495},
      url = {http://link.aip.org/link/?PFB/3/1485/1},
      doi = {http://dx.doi.org/10.1063/1.859716}
    }
    					
    E.-S. Kim, A. M. Sessler & J. S. Wurtele Transverse instability in a 50 GeV×50 GeV muon collider ring 1999 Particle Accelerator Conference, 1999. Proceedings of the 1999
    Vol. 5, pp. 3056-3058  
    Abstract: The intense bunch which is called for in the muon collider design will be subject to transverse instability. It has been suggested that tune spread due to BNS damping be used to control the instability. The transverse dynamics in a 50 GeV×50 GeV muon collider ring is examined numerically using a broad-band impedance. In addition to the BNS damping, tune spreads due to chromaticity, amplitude dependent tune shift and the beam-beam interaction are taken into account. It is shown that each of these tune spreads adequately stabilize the transverse dynamics
    BibTeX:
    @article{792144,
      author = {Eun-San Kim and Sessler, A. M. and Wurtele, J. S.},
      title = {Transverse instability in a 50 GeV×50 GeV muon collider ring},
      journal = {Particle Accelerator Conference, 1999. Proceedings of the 1999},
      year = {1999},
      volume = {5},
      pages = {3056-3058},
      doi = {http://dx.doi.org/10.1109/PAC.1999.792144}
    }
    					
    E.-S. Kim, A. M. Sessler & J. S. Wurtele Analysis of the longitudinal collective behavior in a 50GeV x 50GeV muon collider ring 1999 Phys. Rev. ST Accel. Beams
    Vol. 2 (5), pp. 051001  
    Abstract: Simulations of the longitudinal instability in the 50GeV×50GeV muon collider ring have been performed. Operation of the ring close to the slippage factor η1≃10-6, such that synchrotron motion is frozen, minimizes the need for rf to maintain the bunch length. However, there is still an energy spread due to the bunch wake. For design parameters of the ring, this induced energy is too large and must be controlled. This paper demonstrates that the bunch wake may be compensated for by two rf cavities with low rf voltages. These studies were made at the nominal design point, and sensitivities to errors were explored. It is seen that the small energy spread of the beam (δE/E=3×10-5) in the 50GeV×50GeV muon collider ring can be maintained during the 1000 turn lifetime of the muons. Controlled beam dynamics requires proper choice of rf parameters (rf voltage, rf frequency, and phase offset) for two cavities; these parameters depend on the ring design through the impedance, beam pipe radius, and momentum compaction. The simulation also shows that the computation of wake field using bins of variable width (each with a constant number of macroparticles in each bin) gives an accurate wake and also yields reduced computing time compared to an evaluation of the wake as the direct sum over the wakes of all preceding macroparticles.
    BibTeX:
    @article{PhysRevSTAB.2.051001,
      author = {Kim, Eun-San and Sessler, Andrew M. and Wurtele, Jonathan S.},
      title = {Analysis of the longitudinal collective behavior in a 50GeV x 50GeV muon collider ring},
      journal = {Phys. Rev. ST Accel. Beams},
      publisher = {American Physical Society},
      year = {1999},
      volume = {2},
      number = {5},
      pages = {051001},
      doi = {http://dx.doi.org/10.1103/PhysRevSTAB.2.051001}
    }
    					
    F.-S. Kim, A. R. Sessler & J. S. Wurtele Longitudinal instability in a 50 GeV×50 GeV muon collider ring 1999 Particle Accelerator Conference, 1999. Proceedings of the 1999
    Vol. 5, pp. 3053-3055  
    Abstract: Simulations of the longitudinal dynamics in 50 GeV×50 GeV muon collider ring have been performed. Operation of the ring close to the slippage factor η1&sime;10-6, such that synchrotron motion is frozen, minimizes the need for RF to maintain the bunch length. Without appropriate RF compensation, however, the bunch wake induces an intolerable head-to-tail energy spread. This paper demonstrates that the bunch wake may be compensated by two RF cavities with low RF voltages. With this RF setup the small energy spread of the beam (δE/E=3×10-5) in the 50 GeV×50 GeV muon collider ring can be maintained during the 1000 turn lifetime of the muons. These studies were made at the nominal design point, and sensitivities to errors were explored. The simulation also demonstrates that the computation of the wake field using bins of variable width (each with a constant number of macroparticles) accurately reproduces the wake and yields reduced computing time compared to the evaluation of the wake as the direct sum over the wakes of all preceding macroparticles
    BibTeX:
    @article{792143,
      author = {Fun-San Kim and Sessler, A. R. and Wurtele, J. S.},
      title = {Longitudinal instability in a 50 GeV×50 GeV muon collider ring},
      journal = {Particle Accelerator Conference, 1999. Proceedings of the 1999},
      year = {1999},
      volume = {5},
      pages = {3053-3055},
      doi = {http://dx.doi.org/10.1109/PAC.1999.792143}
    }
    					
    R. Kirkwood, J. S. Wurtele & N. J. Fisch Observation of amplification of a 1ps pulse by SRS of a 1 ns pulse in a plasma with conditions relevant to pulse compression 2005 APS Meeting Abstracts (UCRL-CONF-216926), pp. 1014  
    Abstract: We have observed the amplification of a 1 ps, 1200 nm, probe pulse when counter propagating with a 1ns, 1 x 10^15 W/cm^2, 1064 nm pump pulse, in a He gas plasma created by the pump. When the gas and plasma density is adjusted to match the resonance condition for the probe to seed the stimulated Raman scattering (SRS) of the pump (˜ 1 x 10^19 e/cm^3) the transmitted probe energy is enhanced by 20x to 30x its value off resonance, and as much as 4 mJ of energy is transferred. This is the first demonstration that a 1ns pump beam can significantly amplify an ultra short pulse by SRS in a plasma that can survive irradiation by the pump, and is therefore attractive for compression of the pump when the interaction length is increased. Experiments both at reduced pump intensity, and with an 1124 nm wavelength probe interacting in a 2.5 x 10^18 e/ cm^3 plasma, show a strong scaling of amplification with the resonant density and probe wavelength, and a weaker scaling with pump intensity. This work was performed under the auspices of the U.S. Department of Energy by Univ. of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.
    BibTeX:
    @conference{2005APS..DPPBO1014K,
      author = {Kirkwood, R. and Wurtele, J. S. and Fisch, N. J.},
      title = {Observation of amplification of a 1ps pulse by SRS of a 1 ns pulse in a plasma with conditions relevant to pulse compression},
      journal = {APS Meeting Abstracts},
      year = {2005},
      number = {UCRL-CONF-216926},
      pages = {1014},
      note = {Contributed to the 46th Annual Meeting of the APS Division of Plasma Physics, Denver, Colorado, 24 - 28 Oct 2005}
    }
    					
    P. Kwok, P. Chen, D. Cline, W. Barletta, S. Berridge, W. Bugg, C. Bula, S. Chattopadhyay, W. Craddock, I. Hsu, R. Iverson, T. Katsouleas, P. Lai, W. Leemans, R. Liou, K. T. McDonald, D. D. Meyerhofer, K. Nakajima, H. Nakanishi, C. K. Ng, Y. Nishida, J. Norem, A. Ogata, J. Rosenzweig, M. Ross, A. Sessler, T. Shintake, J. Spencer, J. J. Su, A. W. Weidemann, G. Westenskow, D. Whittum, R. Williams & J. S. Wurtele Progress on plasma lens experiments at the Final Focus Test Beam 1995 Particle Accelerator Conference, 1995., Proceedings of the 1995
    Vol. 4, pp. 2135-2137  
    Abstract: The proposal to perform a series of plasma lens experiments at the Final Focus Test Beam at SLAC has been described earlier. We report on our progress towards validation of concepts involved in the experiments, including the laser ionized plasma production test, development of the supersonic gas jet as the plasma source, and study on focused beam size measurement techniques. Most importantly, the effects of background events due to plasma lenses in future linear collider detectors, such as that in the NLC, are studied in details and are shown to be within detector tolerances
    BibTeX:
    @article{505479,
      author = {Kwok, P. and Chen, P. and Cline, D. and Barletta, W. and Berridge, S. and Bugg, W. and Bula, C. and Chattopadhyay, S. and Craddock, W. and Hsu, I. and Iverson, R. and Katsouleas, T. and Lai, P. and Leemans, W. and Liou, R. and McDonald, K. T. and Meyerhofer, D. D. and Nakajima, K. and Nakanishi, H. and Ng, C. K. and Nishida, Y. and Norem, J. and Ogata, A. and Rosenzweig, J. and Ross, M. and Sessler, A. and Shintake, T. and Spencer, J. and Su, J. J. and Weidemann, A. W. and Westenskow, G. and Whittum, D. and Williams, R. and Wurtele, J. S.},
      title = {Progress on plasma lens experiments at the Final Focus Test Beam},
      journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995},
      year = {1995},
      volume = {4},
      pages = {2135-2137},
      doi = {http://dx.doi.org/10.1109/PAC.1995.505479}
    }
    					
    H. J. Lee, P. .J. Mardahl, G. Penn & J. S. Wurtele Simulation of laser pulse amplification in a plasma by a counterpropagating wave 2002 Plasma Science, IEEE Transactions on
    Vol. 30 (1), pp. 40-41  
    Abstract: Raman amplification of a short laser pulse by a counter-propagating pump in a plasma is simulated with a one-dimensional electromagnetic particle-in-cell code. With a large growth rate due to three wave interaction, the pump pulse is almost totally depleted and the seed pulse is amplified significantly by the transferred energy. A moving window is adopted to enhance simulation efficiency for long interaction length
    BibTeX:
    @article{1003913,
      author = {Lee, H. J. and Mardahl, P .J. and Penn, G. and Wurtele, J. S.},
      title = {Simulation of laser pulse amplification in a plasma by a counterpropagating wave},
      journal = {Plasma Science, IEEE Transactions on},
      year = {2002},
      volume = {30},
      number = {1},
      pages = {40-41},
      doi = {http://dx.doi.org/10.1109/TPS.2002.1003913}
    }
    					
    W. P. Leemans, D. Rodgers, P. E. Catravas, G. Fubiani, C. G. R. Geddes, E. Esarey, B. A. Shadwick, G. J. H. Brussaard, J. van Tilborg, S. Chattopadhyay, J. S. Wurtele, L. Archambault, M. R. Dickinson, S. DiMaggio, R. Short, K. L. Barat, R. Donahue, J. Floyd, A. Smith & E. Wong P. L. Colestock & S. Kelley (Hrsg.) Laser wakefield accelerator experiments at LBNL 2001 The ninth workshop on advanced accelerator concepts
    Vol. 569 (1), pp. 136-145  
    Abstract: The status is presented of the laser wakefield acceleration research at the l'OASIS laboratory of the Center for Beam Physics at LBNL. Experiments have been performed on laser driven production of relativistic electron beams from plasmas using a high repetition rate (10 Hz), high power (10 TW) Ti:sapphire (0.8 µm) laser system. Large amplitude plasma waves have been excited in the self-modulated laser wakefield regime by tightly focusing (spot diameter 8 µm) a single high power (<=10 TW), ultra-short (>=50 fs) laser pulse onto a high density (>1019 cm--3) pulsed gasjet (length 1.2 mm). Nuclear activation measurements in lead and copper targets indicate the production of electrons with energy in excess of 25 MeV. This result was confirmed by electron distribution measurements using a bending magnet spectrometer. Progress on implementing the colliding pulse laser injection method is also presented. This method is expected to produce low emittance (<1pi mm-mrad), low energy spread (<1%), ultrashort (fs), 40 MeV electron bunches containing 107 electrons/bunch.
    BibTeX:
    @conference{leemans:136,
      author = {W. P. Leemans and D. Rodgers and P. E. Catravas and G. Fubiani and C. G. R. Geddes and E. Esarey and B. A. Shadwick and G. J. H. Brussaard and J. van Tilborg and S. Chattopadhyay and J. S. Wurtele and L. Archambault and M. R. Dickinson and S. DiMaggio and R. Short and K. L. Barat and R. Donahue and J. Floyd and A. Smith and E. Wong},
      title = {Laser wakefield accelerator experiments at LBNL},
      journal = {The ninth workshop on advanced accelerator concepts},
      publisher = {AIP},
      year = {2001},
      volume = {569},
      number = {1},
      pages = {136-145},
      url = {http://link.aip.org/link/?APC/569/136/1},
      doi = {http://dx.doi.org/10.1063/1.1384344}
    }
    					
    W. P. Leemans, P. Volfbeyn, K. Z. Guo, S. Chattopadhyay, C. B. Schroeder, B. A. Shadwick, P. B. Lee, J. S. Wurtele & E. Esarey Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection 1998 The 39th annual meeting of division of plasma physics of APS
    Vol. 5 (5), pp. 1615-1623  
    Abstract: Plasma-based accelerators are discussed in which high-power short pulse lasers are the power source, suitably tailored plasma structures provide guiding of the laser beam and support large accelerating gradients, and an optical scheme is used to produce time-synchronized ultrashort electron bunches. From scaling laws laser requirements are obtained for development of compact high-energy accelerators. Simulation results of laser guiding and wakefield excitation in plasma channels, as well as laser-based injection of particles into a plasma wake, are presented. Details of the experimental program at Lawrence Berkeley National Laboratory on laser guiding, laser wakefield-based accelerators, and laser triggered injection are given.
    BibTeX:
    @conference{leemans:1615,
      author = {W. P. Leemans and P. Volfbeyn and K. Z. Guo and S. Chattopadhyay and C. B. Schroeder and B. A. Shadwick and P. B. Lee and J. S. Wurtele and E. Esarey},
      title = {Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection},
      journal = {The 39th annual meeting of division of plasma physics of APS},
      publisher = {AIP},
      year = {1998},
      volume = {5},
      number = {5},
      pages = {1615-1623},
      url = {http://link.aip.org/link/?PHP/5/1615/1},
      doi = {http://dx.doi.org/10.1063/1.872820}
    }
    					
    C. L. Lin, S. C. Chen, J. S. Wurtele, R. Temkin & B. Danly Design and modeling of a 17 GHz photocathode RF gun 1991 Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE
    Vol. 4, pp. 2026-2028  
    Abstract: The performance of a high-frequency (17-GHz), high accelerating gradient (250 MV/m) photocathode RF gun is studied with the particle-in-cell code MAGIC. For the parameter regime of interest, i.e., bunch charge smaller than 1 nC and bunch length shorter than 2 ps, space-charge forces and finite-bunch-length effects are less significant in determining the beam quality than nonlinear RF forces are. The cavity geometry, RF phase for photoemission, cathode size, and current density are being optimized to obtain high-quality beams. Preliminary results are presented
    BibTeX:
    @article{164858,
      author = {Lin, C. L. and Chen, S. C. and Wurtele, J. S. and Temkin, R. and Danly, B.},
      title = {Design and modeling of a 17 GHz photocathode RF gun},
      journal = {Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE},
      year = {1991},
      volume = {4},
      pages = {2026-2028},
      doi = {http://dx.doi.org/10.1109/PAC.1991.164858}
    }
    					
    L. C. L. Lin, S. C. Chen, J. Gonichon, S. Trotz & J. S. Wurtele Waveguide side-wall coupling in RF guns 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 4, pp. 2699-2701  
    Abstract: Waveguide side-wall coupling for RF guns is investigated both theoretically and experimentally. We model this aperture-coupling problem by an integral equation which is solved by the method of moments. The analysis yields an equivalent circuit representation of the system. Of the two normal modes of cavity resonance, the π-mode and 0-mode, we show that only the π-mode is excited. Experimental results show good agreement with theory
    BibTeX:
    @article{309433,
      author = {Lin, L. C. -L. and Chen, S. C. and Gonichon, J. and Trotz, S. and Wurtele, J. S.},
      title = {Waveguide side-wall coupling in RF guns},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {4},
      pages = {2699-2701},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309433}
    }
    					
    L. C. L. Lin, S. C. Chen & J. S. Wurtele An equivalent network analysis of waveguide broad-wall coupled RF gun structures 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 384 (2-3), pp. 274-284  
    Abstract: An equivalent network for a waveguide broad-wall coupled RF gun cavity is derived and solved using a combination of different techniques. The cavity consists of two cylindrical cells coupled via an iris with an exit hole in the second cell. Using the small aperture approximation, the coupling between the rectangular waveguide and the two cylindrical cells (without the iris, the exit hole, and ohmic losses) is rigorously represented by an equivalent network. The circuit elements of this network (as a function of geometry and frequency) are found from first principles. The iris, the exit hole, and ohmic losses are then modeled as reactive and resistive elements, respectively; their values are extracted using a numerical field solver. The frequency domain behaviour of the whole waveguide broad-wall coupled cavity system is completely characterized by this model. The resultant equivalent network is well approximated by two driven coupled oscillators. From this model, we show that the desired [pi]-mode can be selectively excited by properly tuning the gun. Predictions based on this theory agree well with experimental results.
    BibTeX:
    @article{Lin:1997uq,
      author = {Lin, Leon C. -L. and Chen, S. C. and Wurtele, J. S.},
      title = {An equivalent network analysis of waveguide broad-wall coupled RF gun structures},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {384},
      number = {2-3},
      pages = {274--284},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPCMY9-1K/1/b194984564fb48da7d2176b21863b28b}
    }
    					
    L. C. L. Lin, S. C. Chen & J. S. Wurtele Waveguide broad-wall coupling for RF guns 1995 Particle Accelerator Conference, 1995., Proceedings of the 1995
    Vol. 2, pp. 954-956  
    Abstract: A theoretical analysis of the waveguide broad-wall coupling of RF gun structures is presented. The analysis of this three dimensional problem yields an equivalent circuit whose elements are either directly calculated from the frequency and geometry of the gun, or are inferred from the two dimensional numerical solver URMEL. Good agreement between experiment and theory is seen in cold tests of our 17 GHz 1½-cell RF gun
    BibTeX:
    @article{505093,
      author = {Lin, L. C. -L. and Chen, S. C. and Wurtele, J. S.},
      title = {Waveguide broad-wall coupling for RF guns},
      journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995},
      year = {1995},
      volume = {2},
      pages = {954-956},
      doi = {http://dx.doi.org/10.1109/PAC.1995.505093}
    }
    					
    L. C. L. Lin, J. S. Wurtele & S. C. Chen On the frequency scalings of RF guns 1995 Particle Accelerator Conference, 1995., Proceedings of the 1995
    Vol. 2, pp. 951-953  
    Abstract: A frequency scaling law for RF guns is derived from the normalized Vlasov-Maxwell equations. It shows that higher frequency RF guns can generate higher brightness beams under the assumption that the accelerating gradient and all beam and structure parameters are scaled with the RF frequency. Numerical simulation results using MAGIC confirm the scaling law. The scaling of the wakefield is discussed. A discussion of the range of applicability of the law is presented
    BibTeX:
    @article{505092,
      author = {Lin, L. C. -L. and Wurtele, J. S. and Chen, S. C.},
      title = {On the frequency scalings of RF guns},
      journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995},
      year = {1995},
      volume = {2},
      pages = {951-953},
      doi = {http://dx.doi.org/10.1109/PAC.1995.505092}
    }
    					
    R. Lindberg, A. Charman & J. Wurtele Reduced kinetic description of weakly-driven plasma waves 2008 Phys. Plasmas
    Vol. 15, pp. 055911  
    Abstract: A model of kinetic effects in Langmuir wave dynamics is presented using a nonlinear distribution function that includes particle separatrix crossing and self-consistent electrostatic evolution. This model is based on the adiabatic motion of electrons in the wave to describe Bernstein?Greene?Kruskal-like Langmuir waves over a wide range of temperatures (0.1< k?D < 0.4). The asymptotic distribution function yields a nonlinear frequency shift of the Langmuir wave that agrees well with Vlasov simulations, and can furthermore be used to determine the electrostatic energy required to develop the phase-mixed, asymptotic state. From this incoherent energy, energy conservation is employed to determine a simplified model of nonlinear Landau damping. The resulting nonlinear, dynamic frequency shift and damping are then used in an extended three-wave-type model of driven Langmuir waves and compared to Vlasov simulations in the context of backward Raman scattering.
    BibTeX:
    @article{,
      author = {R.R. Lindberg and A.E. Charman and J.S. Wurtele},
      title = {Reduced kinetic description of weakly-driven plasma waves},
      journal = {Phys. Plasmas},
      year = {2008},
      volume = {15},
      pages = {055911},
      url = {http://pop.aip.org/resource/1/phpaen/v15/i5/p055911_s1},
      doi = {http://dx.doi.org/10.1063/1.2907777}
    }
    					
    R. R. Lindberg Nonlinear and Multi-Wave Effects in Fast-Scale Laser-Plasma Interactions 2007 School: University of California at Berkeley  
    BibTeX:
    @phdthesis{Lindberg,
      author = {Lindberg, R. R.},
      title = {Nonlinear and Multi-Wave Effects in Fast-Scale Laser-Plasma Interactions},
      school = {University of California at Berkeley},
      year = {2007}
    }
    					
    R. R. Lindberg, A. E. Charman & J. S. Wurtele Self-consistent Langmuir waves in resonantly driven thermal plasmas 2007 Phys. of Plasma
    Vol. 14 (12), pp. 122103  
    Abstract: The longitudinal dynamics of a resonantly driven Langmuir wave are analyzed in the limit that the growth of the electrostatic wave is slow compared to the bounce frequency. Using simple physical arguments, the nonlinear distribution function is shown to be nearly invariant in the canonical particle action, provided both a spatially uniform term and higher-order spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of self-consistency with the electrostatic potential yield the basic properties of the nonlinear distribution function, including a frequency shift that agrees closely with driven, electrostatic particle simulations over a range of temperatures. This extends earlier work on nonlinear Langmuir waves by Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] and Dewar [R. L. Dewar, Phys. Plasmas 15, 712 (1972)], and could form the basis of a reduced kinetic treatment of plasma dynamics for accelerator applications or Raman backscatter.
    BibTeX:
    @article{lindberg:122103,
      author = {R. R. Lindberg and A. E. Charman and J. S. Wurtele},
      title = {Self-consistent Langmuir waves in resonantly driven thermal plasmas},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2007},
      volume = {14},
      number = {12},
      pages = {122103},
      url = {http://link.aip.org/link/?PHP/14/122103/1},
      doi = {http://dx.doi.org/10.1063/1.2801714}
    }
    					
    R. R. Lindberg, A. E. Charman & J. S. Wurtele Comparison of the Laser Wakefield Accelerator and the Colliding Beam Accelerator 2002 ADVANCED ACCELERATOR CONCEPTS: Tenth Workshop
    Vol. 647 (1), pp. 727-736  
    Abstract: With the advent of chirped pulse amplification and related technologies, much research been devoted to laser pulse shaping for optimal wake generation in a plasma based accelerator. Also, there has been a recent proposal for a colliding beam accelerator (CBA), which uses a detuned pump laser to enhance a standard LWFA wake. We use analytic scalings and PIC simulations to illustrate optimal wake generation in the LWFA under constraints of maximum laser energy, intensity, and bandwidth. We then compare the optimized LWFA to the CBA, finding that while the addition of a pump will increase the wake of a single pulse, the CBA is inferior to a single- or multiple-pulse LWFA of identical total laser energy.
    BibTeX:
    @conference{lindberg:727,
      author = {R. R. Lindberg and A. E. Charman and J. S. Wurtele},
      title = {Comparison of the Laser Wakefield Accelerator and the Colliding Beam Accelerator},
      journal = {ADVANCED ACCELERATOR CONCEPTS: Tenth Workshop},
      publisher = {AIP},
      year = {2002},
      volume = {647},
      number = {1},
      pages = {727-736},
      url = {http://link.aip.org/link/?APC/647/727/1},
      doi = {http://dx.doi.org/10.1063/1.1524928}
    }
    					
    R. R. Lindberg, A. E. Charman, J. S. Wurtele & L. Friedland Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator 2004 Phys. Rev. Lett.
    Vol. 93 (5), pp. 055001  
    Abstract: A modified version of the plasma beat-wave accelerator scheme is proposed, based on autoresonant phase locking of the Langmuir wave to the slowly chirped beat frequency of the driving lasers by passage through resonance. Peak electric fields above standard detuning limits seem readily attainable, and the plasma wave excitation is robust to large variations in plasma density or chirp rate. This scheme might be implemented in existing chirped pulse amplification or CO2 laser systems.
    BibTeX:
    @article{PhysRevLett.93.055001,
      author = {Lindberg, R. R. and Charman, A. E. and Wurtele, J. S. and Friedland, L.},
      title = {Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {2004},
      volume = {93},
      number = {5},
      pages = {055001},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.93.055001}
    }
    					
    R. R. Lindberg, A. E. Charman, J. S. Wurtele, L. Friedland & B. A. Shadwick Autoresonant beat-wave generation 2006 Phys. of Plasma
    Vol. 13 (12), pp. 123103  
    Abstract: Autoresonance offers an efficient and robust means for the ponderomotive excitation of nonlinear Langmuir waves by phase-locking of the plasma wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. This mechanism is analyzed for the case of a cold, relativistic, underdense electron plasma, and its suitability for particle acceleration is discussed. Compared to traditional approaches, this new autoresonant scheme achieves larger accelerating electric fields for given laser intensity; the plasma wave excitation is much more robust to variations in plasma density; it is largely insensitive to the precise choice of chirp rate, provided only that it is sufficiently slow; and the suitability of the resulting plasma wave for accelerator applications is, in some respects, superior. As in previous schemes, modulational instabilities of the ionic background ultimately limit the useful interaction time, but nevertheless peak electric fields approaching the wave-breaking limit seem readily attainable. The total frequency shift required is only of the order of a few percent of the laser carrier frequency, and might be implemented with relatively little additional modification to existing systems based on chirped pulse amplification techniques, or, with somewhat greater technological effort, using a CO2 or other gas laser system.
    BibTeX:
    @article{lindberg:123103,
      author = {R. R. Lindberg and A. E. Charman and J. S. Wurtele and L. Friedland and B. A. Shadwick},
      title = {Autoresonant beat-wave generation},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2006},
      volume = {13},
      number = {12},
      pages = {123103},
      url = {http://link.aip.org/link/?PHP/13/123103/1},
      doi = {http://dx.doi.org/10.1063/1.2390692}
    }
    					
    B. G. Logan, J. J. Barnard, F. M. Bieniosek, R. H. Cohen, J. E. Coleman, R. C. Davidson, P. C. Efthimion, A. Friedman, E. P. Gilson, W. G. Greenway, L. Grisham, D. P. Grote, E. Henestroza, D. H. H. Hoffmann, I. D. Kaganovich, M. K. Covo, J. W. Kwan, K. N. LaFortune, E. P. Lee, M. Leitner, S. M. Lund, A. W. Molvik, P. Ni, G. E. Penn, L. J. Perkins, H. Qin, P. K. Roy, A. B. Sefkow, P. A. Seidl, W. Sharp, E. A. Startsev, J.-L. Vay, W. L. Waldron, J. S. Wurtele, D. Welch, G. A. Westenskow & S. S. Yu Heavy ion fusion science research for high energy density physics and fusion applications 2008 Journal of Physics: Conference Series
    Vol. 112 (3), pp. 032029 (8pp)  
    Abstract: During the past two years, the U.S. heavy ion fusion science program has made significant experimental and theoretical progress in simultaneous transverse and longitudinal beam compression, ion-beam-driven warm dense matter targets, high brightness beam transport, advanced theory and numerical simulations, and heavy ion target designs for fusion. First experiments combining radial and longitudinal compression of intense ion beams propagating through background plasma resulted in on-axis beam densities increased by 700X at the focal plane. With further improvements planned in 2007, these results will enable initial ion beam target experiments in warm dense matter to begin next year at LBNL. We are assessing how these new techniques apply to low-cost modular fusion drivers and higher-gain direct-drive targets for inertial fusion energy.
    BibTeX:
    @article{1742-6596-112-3-032029,
      author = {B G Logan and J J Barnard and F M Bieniosek and R H Cohen and J E Coleman and R C Davidson and P C Efthimion and A Friedman and E P Gilson and W G Greenway and L Grisham and D P Grote and E Henestroza and D H H Hoffmann and I D Kaganovich and M K Covo and J W Kwan and K N LaFortune and E P Lee and M Leitner and S M Lund and A W Molvik and P Ni and G E Penn and L J Perkins and H Qin and P K Roy and A B Sefkow and P A Seidl and W Sharp and E A Startsev and J-L Vay and W L Waldron and J S Wurtele and D Welch and G A Westenskow and S S Yu},
      title = {Heavy ion fusion science research for high energy density physics and fusion applications},
      journal = {Journal of Physics: Conference Series},
      year = {2008},
      volume = {112},
      number = {3},
      pages = {032029 (8pp)},
      url = {http://stacks.iop.org/1742-6596/112/032029}
    }
    					
    M. Gullans, J. S. Wurtele, G. Penn & A. Zholents A source of coherent soft x-ray radiation based on high-order harmonic generation and free electron lasers 2006 (MOPCH045)  
    Abstract: We examine a scheme for a Free Electron Laser (FEL) harmonic amplifier seeded by a 30-nm wavelength signal produced using a process of High-order Harmonic Generation (HHG). The seed is first amplified in an optical klystron from 100 kW to 30 MW using a 1 GeV electron beam and then is used for an energy modulation of electrons in the downstream undulator. Subsequently, a 100MW level of radiation at shorter wavelengths down to 4 nm is obtained by bunching the energy modulated electrons and passing the bunched beam through an undulator tuned to the desired harmonic of 30 nm. to the case where the same total length of undulator is used as a simple modulator without a magnetic chicane. The modulated beam is then bunched in another magnetic chicane, and radiates at a higher harmonic of the HHG signal in the final undulator. This undulator has a period of 1.5 cm, is 12 m long, and is tuned to the eighth harmonic of the HHG seed, or 3.75 nm wavelength. The break sections between undulators are each 1 m long. The first break section contains a dispersive element generating an R 56 of 30 microns. The second break section has another dispersive element with an R56 of 7.5 microns, to yield bunching at the eight harmonic. A sketch of the configuration is shown in Figure 1. Except for the use of the optical klystron, this design is similar to earlier designs for producing FEL output at a harmonic of a laser seed [5, 6].
    BibTeX:
    @conference{Gullans:MOPCH045,
      author = {M. Gullans, and J. S. Wurtele, and G. Penn, and A. Zholents},
      title = {A source of coherent soft x-ray radiation based on high-order harmonic generation and free electron lasers},
      year = {2006},
      number = {MOPCH045},
      note = {Contributed to European Particle Accelerator Conference (EPAC 06), Edinburgh, Scotland, 26-30 Jun 2006}
    }
    					
    M. Harrison, S. D. Holmes, J. M. Paterson & J. S. Wurtele Summer Study on the New Directions in High-energy Physics (Snowmass 1996), Snowmass, Colorado Summary Report from the Accelerator Working Group 1996  
    Abstract: The Accelerator Working Group at Snowmass discussed possibilities for new accelerator facilities in the post-LHC era. Included were discussions of Tevatron luminosity upgrades, next generation (e+e-) linear colliders, muon colliders, very high energy hadron colliders, and advanced acceleration techniques. The emphasis was on identification of required R&D and establishment of reasonable performance goals. Activities of the five working groups are summarized.
    BibTeX:
    @conference{Harrison:830206,
      author = {M. Harrison, and S. D. Holmes, and J. M. Paterson, and J. S. Wurtele},
      title = {Summary Report from the Accelerator Working Group},
      year = {1996},
      note = {Contributed to DPF / DPB, Snowmass, Colorado, 25 Jun - 12 July 1996},
      doi = {OSTI/830206}
    }
    					
    M. S. Hur, H. Suk, G. Kim, R. Lindberg, A. Charman & J. S. Wurtele Ultraintense and Ultrashort Laser Pulses from Raman Amplification in Plasma for Laser-Plasma 2005 (TPAE054)  
    Abstract: We present analysis and simulations of electron trapping effect in the Raman pulse amplification in plasma. An ultraintense and ultrashort laser pulse is a very essential part in an advanced acceleration scheme using laser and plasma. Recently many prominent experimental observations and simulations were reported, where laser pulses of a few terawatt in power and less than 100 fs in the duration were used. To make such strong pulses, a novel scheme of using Raman backscatter in plasma was proposed and has been studied intensively. The Raman amplification in plasma does not have a restriction in material damage threshold. However, for the new amplifier to be a promising alternative of the CPA technique, more extensive studies on various issues are required. One of the fundamental issues is the electron kinetic effect such as particle trapping or wavebreaking. We describe averaged-particlein-cell (aPIC) scheme to simulate the Raman amplification system and discuss the particle trapping effect using the aPIC model.
    BibTeX:
    @conference{Hur:TPAE054,
      author = {M. S. Hur, and H. Suk, and G. Kim, and R. Lindberg, and A. Charman, and J. S. Wurtele},
      title = {Ultraintense and Ultrashort Laser Pulses from Raman Amplification in Plasma for Laser-Plasma},
      year = {2005},
      number = {TPAE054},
      note = {Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee}
    }
    					
    M.M. Alsharo'a & et. al. Recent Progress in Neutrino Factory and Muon Collider Research within the Muon Collaboration 2003 Phys. Rev. ST Accel. Beams
    Vol. 6, pp. 081001  
    Abstract: We describe the status of our effort to realize a first neutrino factory and the progress made in understanding the problems associated with the collection and cooling of muons towards that end. We summarize the physics that can be done with neutrino factories as well as with intense cold beams of muons. The physics potential of muon colliders is reviewed, both as Higgs Factories and compact high energy lepton colliders. The status and timescale of our research and development effort is reviewed as well as the latest designs in cooling channels including the promise of ring coolers in achieving longitudinal and transverse cooling simultaneously. We detail the efforts being made to mount an international cooling experiment to demonstrate the ionization cooling of muons.
    BibTeX:
    @article{alsharoa-2003-6,
      author = {M.M. Alsharo'a, and et. al.},
      title = {Recent Progress in Neutrino Factory and Muon Collider Research within the Muon Collaboration},
      journal = {Phys. Rev. ST Accel. Beams},
      year = {2003},
      volume = {6},
      pages = {081001},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:hep-ex/0207031}
    }
    					
    N. Madsen, G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, C. Bray, E. Butler, C. L. Cesar, S. Chapman, M. Charlton, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, J. S. Hangst, W. N. Hardy, M. E. Hayden, A. J. Humphries, R. Hydomako, S. Jonsell, L. V. J�rgensen, L. Kurchaninov, R. Lambo, S. Menary, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, S. S. E. Nasr, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki Search for trapped antihydrogen in ALPHA 2011 Can. J. Phys.
    Vol. 89(1), pp. 7-16  
    Abstract: Antihydrogen spectroscopy promises precise tests of the symmetry of matter and antimatter, and can possibly offer new insights into the baryon asymmetry of the universe. Antihydrogen is, however, difficult to synthesize and is produced only in small quantities. The ALPHA collaboration is therefore pursuing a path towards trapping cold antihydrogen to permit the use of precision atomic physics tools to carry out comparisons of antihydrogen and hydrogen. ALPHA has addressed these challenges. Control of the plasma sizes has helped to lower the influence of the multipole field used in the neutral atom trap, and thus lowered the temperature of the created atoms. Finally, the first systematic attempt to identify trapped antihydrogen in our system is discussed. This discussion includes special techniques for fast release of the trapped anti-atoms, as well as a silicon vertex detector to identify antiproton annihilations. The silicon detector reduces the background of annihilations, including background from antiprotons that can be mirror trapped in the fields of the neutral atom trap. A description of how to differentiate between these events and those resulting from trapped antihydrogen atoms is also included.
    BibTeX:
    @article{,
      author = {N. Madsen and G. B. Andresen and M. D. Ashkezari and M. Baquero-Ruiz and W. Bertsche and P. D. Bowe and C. Bray and E. Butler and C. L. Cesar and S. Chapman and M. Charlton and J. Fajans and T. Friesen and M. C. Fujiwara and D. R. Gill and J. S. Hangst and W. N. Hardy and M. E. Hayden and A. J. Humphries and R. Hydomako and S. Jonsell and L. V. J�rgensen and L. Kurchaninov and R. Lambo and S. Menary and P. Nolan and K. Olchanski and A. Olin and A. Povilus and P. Pusa and F. Robicheaux and E. Sarid and S. Seif El Nasr and D. M. Silveira and C. So and J. W. Storey and R. I. Thompson and D. P. van der Werf and J. S. Wurtele and Y. Yamazaki},
      title = {Search for trapped antihydrogen in ALPHA},
      journal = {Can. J. Phys.},
      year = {2011},
      volume = {89(1)},
      pages = {7-16},
      url = {http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=eng&journal=cjp&volume=89&year=2011&issue=1&msno=p10-085},
      doi = {http://dx.doi.org/10.1139/P10-085}
    }
    					
    V. M. Malkin, N. J. Fisch & J. S. Wurtele Compression of powerful x-ray pulses to attosecond durations by stimulated Raman backscattering in plasmas 2007 Phys. Rev. E (Statistical, Nonlinear, and Soft Matter Physics)
    Vol. 75 (2), pp. 026404  
    Abstract: Backward Raman amplification (BRA) in plasmas holds the potential for longitudinal compression and focusing of powerful x-ray pulses. In principle, this method is capable of producing pulse intensities close to the vacuum breakdown threshold by manipulating the output of planned x-ray sources. The minimum wavelength limit of BRA applicability to compression of laser pulses in plasmas is found.
    BibTeX:
    @article{malkin:026404,
      author = {V. M. Malkin and N. J. Fisch and J. S. Wurtele},
      title = {Compression of powerful x-ray pulses to attosecond durations by stimulated Raman backscattering in plasmas},
      journal = {Phys. Rev. E (Statistical, Nonlinear, and Soft Matter Physics)},
      publisher = {APS},
      year = {2007},
      volume = {75},
      number = {2},
      pages = {026404},
      url = {http://link.aps.org/abstract/PRE/v75/e026404},
      doi = {http://dx.doi.org/10.1103/PhysRevE.75.026404}
    }
    					
    P. Mardahl, H. J. Lee, G. Penn, J. S. Wurtele & N. J. Fisch Intense laser pulse amplification using Raman backscatter in plasma channels 2002 Phys. Rev. A
    Vol. 296 (2-3), pp. 109-116  
    Abstract: It has been proposed that the Raman backscatter interaction in a plasma can be used to amplify ultra-intense laser pulses. To accomplish this, energy is transferred from a long drive pulse at frequency [omega]pump to an intense seed pulse at frequency [omega]seed, with a Langmuir plasma wave at frequency wp mediating the transfer; the frequencies are chosen to satisfy the resonant condition [omega]p=[omega]pump-[omega]seed. Diffraction of the pulses limits the interaction length in a uniform plasma, and hence the energy transfer between the pulses. However in a parabolic plasma density channel it is shown, through two-dimensional particle-in-cell simulations, that such a plasma channel can be used to guide both the amplified and drive pulses over an interaction distance much greater than a diffraction length. The seed pulse is amplified by a factor of more than 200 in energy for pulses whose widths are matched to the channel size, and achieve a peak intensity of more than 6◊1017†W/cm2. Unmatched pump pulses are seen to generate much smaller gain.
    BibTeX:
    @article{Mardahl:2002qy,
      author = {Mardahl, P. and Lee, H. J. and Penn, G. and Wurtele, J. S. and Fisch, N. J.},
      title = {Intense laser pulse amplification using Raman backscatter in plasma channels},
      journal = {Phys. Rev. A},
      year = {2002},
      volume = {296},
      number = {2-3},
      pages = {109--116},
      url = {http://www.sciencedirect.com/science/article/B6TVM-45FSWFK-2/1/0e0a1c21dcb909f4ad73ed735f12857f}
    }
    					
    K. T. McDonald Expression of Interest in R&D towards a Neutrino Factory Based on a Storage Ring and a Muon Collider 1999 (9911009)  
    Abstract: We are exploring the feasibility of a neutrino factory based on a muon storage ring. In this, beams of nu_mu and nubar_e arise from the decay of mu- particles (or alternatively, nubar_mu and nu_e from mu+). The muons come from the decay of low-energy pions produced by a megawatt proton beam incident on a nuclear target. The muons are captured into a magnetic channel, "cooled" by ionization in liquid hydrogen, accelerated to energy of order 50 GeV, and injected into a storage ring. A nonhorizontal ring can deliver neutrino beams to an on-site detector, as well as to two off-site detectors separated by global distances. Such a neutrino factory is a challenging extension of present accelerator technology. It is also a natural path to a muon collider, in that both facilities share many common elements upstream of their storage rings. Prior to a formal design study, R&D must be performed in several keys areas, such detailed simulations and actual targetry and cooling experiments. This in an excellent opportunity to advance the field of accelerator physics both at national laboratories and at universities.
    BibTeX:
    @misc{mcdonald-1999,
      author = {K.~T. McDonald},
      title = {Expression of Interest in R&D towards a Neutrino Factory Based on a Storage Ring and a Muon Collider},
      year = {1999},
      number = {9911009},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:physics/9911009}
    }
    					
    O. Naaman, J. Aumentado, L. Friedland, J. S. Wurtele & I. Siddiqi Phase-Locking Transition in a Chirped Superconducting Josephson Resonator 2008 Phys. Rev. Lett.
    Vol. 101 (11), pp. 117005  
    Abstract: We observe a sharp threshold for dynamic phase locking in a high-Q transmission line resonator embedded with a Josephson tunnel junction, and driven with a purely ac, chirped microwave signal. When the drive amplitude is below a critical value, which depends on the chirp rate and is sensitive to the junction critical current I0, the resonator is only excited near its linear resonance frequency. For a larger amplitude, the resonator phase locks to the chirped drive and its amplitude grows until a deterministic maximum is reached. Near threshold, the oscillator evolves smoothly in one of two diverging trajectories, providing a way to discriminate small changes in I0 with a nonswitching detector, with potential applications in quantum state measurement.
    BibTeX:
    @article{naaman:117005,
      author = {O. Naaman and J. Aumentado and L. Friedland and J. S. Wurtele and I. Siddiqi},
      title = {Phase-Locking Transition in a Chirped Superconducting Josephson Resonator},
      journal = {Phys. Rev. Lett.},
      publisher = {APS},
      year = {2008},
      volume = {101},
      number = {11},
      pages = {117005},
      url = {http://link.aps.org/abstract/PRL/v101/e117005},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.101.117005}
    }
    					
    J. Notte, J. Fajans, R. Chu & J. S. Wurtele Experimental breaking of an adiabatic invariant 1993 Phys. Rev. Lett.
    Vol. 70 (25), pp. 3900-3903  
    Abstract: When a cylindrical pure electron plasma is displaced from the center of the trap, it performs a bulk circular orbital motion known as the l=1 diocotron mode. The slow application of a perturbing potential to a patch on the trap wall distorts the orbit into a noncircular closed path. Experiments and a simple theoretical model indicate that the area by the loop is an adiabatic invariant. Detailed studies are made of the breaking of the invariant when perturbations are rapidly applied. When the perturbation is applied with discontinuous time derivatives, the invariant breaking greatly exceeds the predictions of the standard theory for smooth perturbations.
    BibTeX:
    @article{PhysRevLett.70.3900,
      author = {Notte, J. and Fajans, J. and Chu, R. and Wurtele, J. S.},
      title = {Experimental breaking of an adiabatic invariant},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1993},
      volume = {70},
      number = {25},
      pages = {3900--3903},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.70.3900}
    }
    					
    J. Notte, A. J. Peurrung, J. Fajans, R. Chu & J. S. Wurtele Asymmetric stable equilibria of non-neutral plasmas 1992 Phys. Rev. Lett.
    Vol. 69 (21), pp. 3056-3059  
    Abstract: A pure electron plasma, confined within an azimuthally symmetric boundary by a coaxial magnetic field, has an equilibrium shape which is cylindrical. We apply perturbations which break the azimuthal symmetry and deform the plasma into a noncircular shape that is stationary in the laboratory frame. These asymmetric equilibria form a broad new class of stable equilibria. A theoretical model correctly predicts the plasma shapes and explains their stability.
    BibTeX:
    @article{PhysRevLett.69.3056,
      author = {Notte, J. and Peurrung, A. J. and Fajans, J. and Chu, R. and Wurtele, J. S.},
      title = {Asymmetric stable equilibria of non-neutral plasmas},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1992},
      volume = {69},
      number = {21},
      pages = {3056--3059},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.69.3056}
    }
    					
    T. Orzechowski, E. Scharlemann, B. Anderson, V. Neil, W. Fawley, D. Prosnitz, S. Yarema, D. Hopkins, A. Paul, A. Sessler & J. S. Wurtele High-gain free electron lasers using induction linear accelerators 1985 Quantum Electronics, IEEE Journal of
    Vol. 21 (7), pp. 831-844  
    Abstract: High-power free electron lasers (FEL's) can be realized using induction linear accelerators as the source of the electron beam. These accelerators are currently capable of producing intense currents (102-104A) at moderately high energy (1-50 MeV). Experiments using a 500 A, 3.3 MeV beam have produced 80 MW of radiation at 34.6 GHz and are in good agreement with theoretical analysis. Future experiments include a high-gain, high-efficiency FEL operating at 10.6 μm using a 50 MeV beam.
    BibTeX:
    @article{1072732,
      author = {Orzechowski, T. and Scharlemann, E. and Anderson, B. and Neil, V. and Fawley, W. and Prosnitz, D. and Yarema, S. and Hopkins, D. and Paul, A. and Sessler, A. and Wurtele, J. S.},
      title = {High-gain free electron lasers using induction linear accelerators},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1985},
      volume = {21},
      number = {7},
      pages = {831-844}
    }
    					
    T. J. Orzechowski, B. Anderson, W. M. Fawley, D. Prosnitz, E. T. Scharlemann, S. Yarema, D. Hopkins, A. C. Paul, A. M. Sessler & J. S. Wurtele Microwave radiation from a high-gain free-electron laser amplifier 1985 Phys. Rev. Lett.
    Vol. 54 (9), pp. 889-892  
    Abstract: A high-gain, high--extraction-efficiency, linearly polarized free-electron laser amplifier has been operated at 34.6 GHz. At low signal levels, exponential gain of 13.4 dB/m has been measured. With a 3-=kW input signal, saturation was observed with an 80-MW output and a 5% extraction efficiency. The results are in good agreement with linear models at small signal levels and nonlinear models at large signal levels.
    BibTeX:
    @article{PhysRevLett.54.889,
      author = {Orzechowski, T. J. and Anderson, B. and Fawley, W. M. and Prosnitz, D. and Scharlemann, E. T. and Yarema, S. and Hopkins, D. and Paul, A. C. and Sessler, A. M. and Wurtele, J. S.},
      title = {Microwave radiation from a high-gain free-electron laser amplifier},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1985},
      volume = {54},
      number = {9},
      pages = {889--892},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.54.889}
    }
    					
    T. J. Orzechowski, B. R. Anderson, J. C. Clark, W. M. Fawley, A. C. Paul, D. Prosnitz, E. T. Scharlemann, S. M. Yarema, D. B. Hopkins, A. M. Sessler & J. S. Wurtele High-Efficiency Extraction of Microwave Radiation from a Tapered-Wiggler Free-Electron Laser 1986 Phys. Rev. Lett.
    Vol. 57 (17), pp. 2172-2175  
    Abstract: We have substantially increased the output power and extraction efficiency of a free-electron laser operating at 34.6 GHz by tapering the wiggler magnetic field. In the exponential-gain regime, the laser exhibited a measured gain of 34 dB/m. With a 50-kW input signal, the amplifier saturated in 1.3 m with a 180-MW output signal. By using a taper that brought the magnetic field at the end of the wiggler down to 45% of its initial (peak) value, we increased the output signal to 1.0 GW. This corresponds to an extraction efficiency of 34%.
    BibTeX:
    @article{PhysRevLett.57.2172,
      author = {Orzechowski, T. J. and Anderson, B. R. and Clark, J. C. and Fawley, W. M. and Paul, A. C. and Prosnitz, D. and Scharlemann, E. T. and Yarema, S. M. and Hopkins, D. B. and Sessler, A. M. and Wurtele, J. S.},
      title = {High-Efficiency Extraction of Microwave Radiation from a Tapered-Wiggler Free-Electron Laser},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1986},
      volume = {57},
      number = {17},
      pages = {2172--2175},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.57.2172}
    }
    					
    R. Palmer, A. Sessler, A. Skrinsky, A. Tollestrup, A. Baltz, S. Caspi, P. Chen, W.-H. Cheng, Y. Cho, D. Cline, E. Courant, R. Fernow, J. Gallardo, A. Garren, H. Gordon, M. Green, R. Gupta, A. Hershcovitch, C. Johnstone, S. Kahn, H. Kirk, T. Kycia, Y. Lee, D. Lissauer, A. Luccio, A. Mclnturff, F. Mills, N. Mokhov, G. Morgan, D. Neuffer, K.-Y. Ng, R. Noble, J. Norem, B. Norum, K. Oide, Z. Parsa, V. Polychronakos, M. Popovic, P. Rehak, T. Roser, R. Rossmanith, R. Scanlan, L. Schachinger, G. Silvestrov, I. Stumer, D. Summers, M. Syphers, H. Takahashi, Y. Torun, D. Trbojevic, W. Turner, A. Van Ginneken, T. Vsevolozhskaya, R. Weggel, E. Willen, W. Willis, D. Winn, J. S. Wurtele & Y. Zhao Muon collider design 1996 Nuclear Physics B - Proceedings Supplements
    Vol. 51 (1), pp. 61-84  
    BibTeX:
    @article{Palmer:1996fj,
      author = {Palmer, R. and Sessler, A. and Skrinsky, A. and Tollestrup, A. and Baltz, A. and Caspi, S. and Chen, P. and Cheng, W-H. and Cho, Y. and Cline, D. and Courant, E. and Fernow, R. and Gallardo, J. and Garren, A. and Gordon, H. and Green, M. and Gupta, R. and Hershcovitch, A. and Johnstone, C. and Kahn, S. and Kirk, H. and Kycia, T. and Lee, Y. and Lissauer, D. and Luccio, A. and Mclnturff, A. and Mills, F. and Mokhov, N. and Morgan, G. and Neuffer, D. and Ng, K-Y. and Noble, R. and Norem, J. and Norum, B. and Oide, K. and Parsa, Z. and Polychronakos, V. and Popovic, M. and Rehak, P. and Roser, T. and Rossmanith, R. and Scanlan, R. and Schachinger, L. and Silvestrov, G. and Stumer, I. and Summers, D. and Syphers, M. and Takahashi, H. and Torun, Y. and Trbojevic, D. and Turner, W. and Van Ginneken, A. and Vsevolozhskaya, T. and Weggel, R. and Willen, E. and Willis, W. and Winn, D. and Wurtele, J. S. and Zhao, Y.},
      title = {Muon collider design},
      journal = {Nuclear Physics B - Proceedings Supplements},
      year = {1996},
      volume = {51},
      number = {1},
      pages = {61--84},
      url = {http://www.sciencedirect.com/science/article/B6TVD-3XXDV68-W/1/f9f7fa9cb7e31e4bc391968c8eda0eab}
    }
    					
    R. B. Palmer, A. Sessler, A. Skrinsky & A. Tollestrup Muon Colliders 1996 AIP CONF.PROC.
    Vol. 372, pp. 3  
    Abstract: Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity mumu colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed.
    BibTeX:
    @article{palmer-1996-372,
      author = {R.~B. Palmer and A. Sessler and A. Skrinsky and A. Tollestrup},
      title = {Muon Colliders},
      journal = {AIP CONF.PROC.},
      year = {1996},
      volume = {372},
      pages = {3},
      url = {http://www.citebase.org/abstract?id=oai:arXiv.org:acc-phys/9602001}
    }
    					
    F. Peinetti, W. Bertsche, J. Fajans, J. S. Wurtele & L. Friedland Numerical studies of driven, chirped Bernstein, Greene, and Kruskal modes 2005 Phys. of Plasma
    Vol. 12 (6), pp. 062112  
    Abstract: Recent experiments showed the possibility of creating long-lived, nonlinear kinetic structures in a pure-electron plasma. These structures, responsible for large-amplitude periodic density fluctuations, were induced by driving the plasma with a weak oscillating drive, whose frequency was adiabatically decreased in time [W. Bertsche, J. Fajans, and L. Friedland, Phys. Rev. Lett. 91, 265003 (2003)]. A one-dimensional analytical model of the system was developed [L. Friedland, F. Peinetti, W. Bertsche, J. Fajans, and J. Wurtele, Phys. Plasmas 11, 4305 (2004)], which pointed out the phenomenon responsible for the modifications induced by the weak drive in the phase-space distribution of the plasma (initially Maxwellian). In order to validate the theory and to perform quantitative comparisons with the experiments, a more accurate description of the system is developed and presented here. The new detailed analysis of the geometry under consideration allows for more precise simulations of the excitation process, in which important physical and geometrical parameters (such as the length of the plasma column) are evaluated accurately. The numerical investigations probe properties and features of the modes not accessible to direct measurement. Due to the presence of two distinct time scales (because of the adiabatic chirp of the drive frequency), a fully two-dimensional numerical study of the system is expected to be rather time consuming. This becomes particularly important when, as here, a large number of comparisons (covering a wide range of drive parameters) are performed. For this reason, a coupled one-dimensional, radially averaged model is derived and implemented in a particle-in-cell code.
    BibTeX:
    @article{peinetti:062112,
      author = {F. Peinetti and W. Bertsche and J. Fajans and J. S. Wurtele and L. Friedland},
      title = {Numerical studies of driven, chirped Bernstein, Greene, and Kruskal modes},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2005},
      volume = {12},
      number = {6},
      pages = {062112},
      url = {http://link.aip.org/link/?PHP/12/062112/1},
      doi = {http://dx.doi.org/10.1063/1.1928251}
    }
    					
    F. Peinetti, F. Peano, G. Coppa & J. S. Wurtele Particle-in-cell method for parallel dynamics in magnetized electron plasmas: Study of high-amplitude BGK modes 2006 J. Comp. Phys.
    Vol. 218 (1), pp. 102-122  
    Abstract: The present paper describes the numerical technique that has been developed, in the framework of the particle-in-cell (PIC) method, to study the dynamics of a nonneutral plasma along the magnetic field lines. In particular, the technique has been employed to simulate the formation and long-term evolution of large-amplitude electrostatic waves experimentally observed in electron plasmas confined in a Penning trap [W. Bertsche, J. Fajans, L. Friedland, Phys. Rev. Lett. 91 (2003) 265003]. Due to the peculiar features of the physical system, namely the existence of different time scales and the presence of a perturbative oscillating potential, ad hoc numerical techniques have been developed. In particular, with a suitable radial decomposition all important two-dimensional phenomena are fully taken into account while keeping the computational effort to that of a standard one-dimensional PIC codes. Moreover, a novel particle loading technique (ergodic loading) has been developed, which ensures a significant reduction of numerical noise. The results obtained with the present technique are in excellent agreement with the experiments [F. Peinetti, W. Bertsche, J. Fajans, J. Wurtele, L. Friedland, Phys. Plasmas 12 (2005) 062112]. Moreover, results presented here furnish clear evidences of the close relationship between the observed nonlinear structures and the Bernstein-Greene-Kruskal modes.
    BibTeX:
    @article{Peinetti:2006ud,
      author = {Peinetti, F. and Peano, F. and Coppa, G. and Wurtele, J. S.},
      title = {Particle-in-cell method for parallel dynamics in magnetized electron plasmas: Study of high-amplitude BGK modes},
      journal = {J. Comp. Phys.},
      year = {2006},
      volume = {218},
      number = {1},
      pages = {102--122},
      url = {http://www.sciencedirect.com/science/article/B6WHY-4JG48VV-2/1/e41a99b3ac88745d0506552cefa60ad0}
    }
    					
    K. D. Pendergast, B. G. Danley, R. J. Temkin & J. S. Wurtele Self-consistent simulation of cyclotron autoresonance maser amplifiers 1988 Plasma Science, IEEE Transactions on
    Vol. 16 (2), pp. 122-128  
    Abstract: A self-consistent, one-dimensional model of the cyclotron autoresonance maser (CARM) amplifier is developed, and numerical simulations based on this model are described. Detailed study results of the CARM gain and efficiency for a wide range of initial energy and velocity spreads are presented. The interaction efficiency is found to be substantially increased when the axial magnetic field is tapered. Efficiencies of greater than 41% are obtained for a 140-GHz CARM amplifier with a tapered axial magnetic field and a 700-kV 4.5-A electron beam with parallel velocity spreads of less than 1%. A discussion of the nonlinear bandwidth and interaction sensitivity to axial-field inhomogeneities is presented
    BibTeX:
    @article{3803,
      author = {Pendergast, K. D. and Danley, B. G. and Temkin, R. J. and Wurtele, J. S.},
      title = {Self-consistent simulation of cyclotron autoresonance maser amplifiers},
      journal = {Plasma Science, IEEE Transactions on},
      year = {1988},
      volume = {16},
      number = {2},
      pages = {122-128},
      doi = {http://dx.doi.org/10.1109/27.3803}
    }
    					
    G. Penn, M. Reinsch & J. S. Wurtele Analytic model of bunched beams for harmonic generation in the low-gain free electron laser regime 2006 Phys. Rev. ST Accel. Beams
    Vol. 9 (6), pp. 060702  
    Abstract: One scheme for harmonic generation employs free electron lasers (FELs) with two undulators: the first uses a seed laser to modulate the energy of the electron beam; following a dispersive element which acts to bunch the beam, the second undulator radiates at a higher harmonic. These processes are currently evaluated using extensive calculations or simulation codes which can be slow to evaluate and difficult to set up. We describe a simple algorithm to predict the output of a harmonic generation beam line in the low-gain FEL regime, based on trial functions for the output radiation. Full three-dimensional effects are included. This method has been implemented as a Mathematicatextregistered package, named campanile, which runs rapidly and can be generalized to include effects such as asymmetric beams and misalignments. This method is compared with simulation results using the FEL code genesis, both for single stages of harmonic generation and for the LUX project, a design concept for an ultrafast x-ray facility, where multiple stages upshift the input laser frequency by factors of up to 200.
    BibTeX:
    @article{PhysRevSTAB.9.060702,
      author = {Penn, G. and Reinsch, M. and Wurtele, J. S.},
      title = {Analytic model of bunched beams for harmonic generation in the low-gain free electron laser regime},
      journal = {Phys. Rev. ST Accel. Beams},
      publisher = {American Physical Society},
      year = {2006},
      volume = {9},
      number = {6},
      pages = {060702},
      doi = {http://dx.doi.org/10.1103/PhysRevSTAB.9.060702}
    }
    					
    G. Penn, P. H. Stoltz, J. R. Cary & J. S. Wurtele Boris push with spatial stepping 2003 J. of Phys. G: Nuclear and Particle Physics
    Vol. 29 (8), pp. 1719-1722  
    Abstract: The Boris push is commonly used in plasma physics simulations because of its speed and stability. It is second-order accurate, requires only one field evaluation per time step, and has good conservation properties. However, for accelerator simulations it is convenient to propagate particles in z down a changing beamline. A 'spatial Boris push' algorithm has been developed which is similar to the Boris push but uses a spatial coordinate as the independent variable, instead of time. This scheme is compared to the fourth-order Runge-Kutta algorithm, for two simplified muon beam lattices: a uniform solenoid field, and a 'FOFO' lattice where the solenoid field varies sinusoidally along the axis. Examination of the canonical angular momentum, which should be conserved in axisymmetric systems, shows that the spatial Boris push improves accuracy over long distances.
    BibTeX:
    @article{0954-3899-29-8-337,
      author = {G. Penn and P. H. Stoltz and J. R. Cary and J. S. Wurtele},
      title = {Boris push with spatial stepping},
      journal = {J. of Phys. G: Nuclear and Particle Physics},
      year = {2003},
      volume = {29},
      number = {8},
      pages = {1719-1722},
      url = {http://stacks.iop.org/0954-3899/29/1719}
    }
    					
    G. Penn & J. S. Wurtele Beam Envelope Equations for Cooling of Muons in Solenoid Fields 2000 Phys. Rev. Lett.
    Vol. 85 (4), pp. 764-767  
    Abstract: Muon cooling is a critical component of the proposed muon collider and neutrino factory. Previous studies of cooling channels have tracked single muons through the channel, which requires many particles for good statistics and does not lend itself to an understanding of channel dynamics. In this paper, a system of moment equations are derived which captures the major aspects of cooling: interactions with material and acceleration by radio frequency (rf) cavities. A general analysis of solenoid lattice types compares well with prior simulations and indicates new directions for study.
    BibTeX:
    @article{PhysRevLett.85.764,
      author = {Penn, G. and Wurtele, J. S.},
      title = {Beam Envelope Equations for Cooling of Muons in Solenoid Fields},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {2000},
      volume = {85},
      number = {4},
      pages = {764--767},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.85.764}
    }
    					
    G. Penn & J. S. Wurtele An analysis of BNS damping techniques in storage rings and colliders 1999 Particle Accelerator Conference, 1999. Proceedings of the 1999
    Vol. 5, pp. 3059-3061  
    Abstract: Transverse instabilities in linacs can be controlled by BNS damping, in which the transverse oscillation frequency is chirped from the head to the tail of the bunch. It has been suggested that this technique could be applied to quasi-isochronous rings, such as are proposed for a muon collider. We adopt a reduced phase space model, taking averages over transverse coordinates and with proscribed longitudinal synchrotron motion, to study the growth of transverse displacements of a bunch in the presence of synchrotron oscillations
    BibTeX:
    @article{792151,
      author = {Penn, G. and Wurtele, J. S.},
      title = {An analysis of BNS damping techniques in storage rings and colliders},
      journal = {Particle Accelerator Conference, 1999. Proceedings of the 1999},
      year = {1999},
      volume = {5},
      pages = {3059-3061},
      doi = {http://dx.doi.org/10.1109/PAC.1999.792151}
    }
    					
    Y. Ping, R. Kirkwood, T. Wang, S. Wilks, N. Fisch, J. Wurtele, C. Joshi & W. Mori Toward Exawatt lasers: amplification and compression of short laser pulses in plasma 2009  
    BibTeX:
    @conference{,
      author = {Y. Ping and R. Kirkwood and T. Wang and S. Wilks and N. Fisch and J. Wurtele and C. Joshi and W. Mori},
      title = {Toward Exawatt lasers: amplification and compression of short laser pulses in plasma},
      booktitle = {Conference on Lasers and Electro-Optics/Pacific Rim 2009 (Optical Society of America, 2009)},
      year = {2009}
    }
    					
    Y. Ping, R. K. Kirkwood, T.-L. Wang, D. S. Clark, S. C. Wilks, N. Meezan, R. L. Berger, J. Wurtele, N. J. Fisch, V. M. Malkin, E. J. Valeo, S. F. Martins & C. Joshi Development of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma 2009 Physics of Plasmas
    Vol. 16 (12), pp. 123113  
    Abstract: Progress on developing a plasma amplifier/compressor based on stimulated Raman scattering of nanosecond laser pulses is reported. Generation of a millijoule seed pulse at a wavelength that is redshifted relative to the pump beam has been achieved using an external Raman gas cell. By interacting the shifted picosecond seed pulse and the nanosecond pump pulse in a gas jet plasma at a density of ? 1019?cm?3, the upper limit of the pump intensity to avoid angular spray of the amplified seed has been determined. The Raman amplification has been studied as a function of the pump and seed intensities. Although the heating of plasma by the nanosecond pump pulse results in strong Landau damping of the plasma wave, an amplified pulse with an energy of up to 14 mJ has been demonstrated, which is, to the best of our knowledge, the highest output energy so far by Raman amplification in a plasma. One-dimensional particle-in-cell simulations indicate that the saturation of amplification is consistent with onset of particle trapping, which might be overcome by employing a shorter seed pulse.
    BibTeX:
    @article{Ping2009,
      author = {Y. Ping and R. K. Kirkwood and T.-L. Wang and D. S. Clark and S. C. Wilks and N. Meezan and R. L. Berger and J. Wurtele and N. J. Fisch and V. M. Malkin and E. J. Valeo and S. F. Martins and C. Joshi},
      title = {Development of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2009},
      volume = {16},
      number = {12},
      pages = {123113},
      url = {http://link.aip.org/link/?PHP/16/123113/1},
      doi = {http://dx.doi.org/10.1063/1.3276739}
    }
    					
    X. Qiu, P. Catravas, M. Babzien, I. Ben-Zvi, J. M. Fang, W. Graves, Y. Liu, R. Malone, I. Mastovsky, Z. Segalov, J. Sheehan, R. Stoner, X. J. Wang & J. S. Wurtele Experiments in nonperturbative electron beam characterization with the MIT microwiggler at the accelerator test facility at BNL 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 393 (1-3), pp. 484-489  
    Abstract: We report first measurements of a single-shot method through which the properties of an electron beam at linac energies may be studied using the spontaneous emission of a micro-wiggler. The setup is simple and the measurement efficient. A simple set of scaling laws describe the natural line width, energy spread and divergence broadening of spontaneous emission in a narrow bandwidth radiation cone. A systematic series of experiments were performed with the MIT Microwiggler at the Accelerator Test Facility at BNL which demonstrated the response of the cone to changes in the beam quality. Estimates of divergence were obtained from the measurements of the radiation cone.
    BibTeX:
    @article{Qiu:1997hl,
      author = {Qiu, X. and Catravas, P. and Babzien, M. and Ben-Zvi, I. and Fang, J. -M. and Graves, W. and Liu, Y. and Malone, R. and Mastovsky, I. and Segalov, Z. and Sheehan, J. and Stoner, R. and Wang, X. -J. and Wurtele, J. S.},
      title = {Experiments in nonperturbative electron beam characterization with the MIT microwiggler at the accelerator test facility at BNL},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {393},
      number = {1-3},
      pages = {484--489},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPTFJX-8W/1/ffa8c3c3f43cc99c96016b4fd58f7751}
    }
    					
    R. Raja & others Summer Study on the Future of Particle Physics (Snowmass 2001), Snowmass, Colorado The Program In Muon And Neutrino Physics: Super Beams, Cold Muon Beams, Neutrino Factory And The Muon Collider 2001  
    BibTeX:
    @conference{Raja:2001be,
      author = {Raja, Rajendran and others},
      title = {The Program In Muon And Neutrino Physics: Super Beams, Cold Muon Beams, Neutrino Factory And The Muon Collider},
      year = {2001},
      note = {Contributed to APS / DPF / DPB},
      doi = {OSTI/784174}
    }
    					
    H. Saito & J. S. Wurtele The linear theory of the circular free-electron laser 1987 Physics of Fluids
    Vol. 30 (7), pp. 2209-2220  
    Abstract: A small signal theory of a free-electron laser (FEL) with a rotating electron beam in a uniform axial magnetic field and in an azimuthal wiggler field (the ``circular'' FEL) is developed. The analysis includes the low and high gain regimes and the influence of longitudinal space-charge forces. It is found that the circular FEL instability has two regimes: a strong pump regime and a negative mass dominated regime. The negative mass regime replaces the weak pump (Raman) regime found for the usual FEL geometry in which the electron beam propagates in the axial direction (the ``linear'' FEL). The dispersion relation is evaluated, and the resulting growth rates are compared with those of the linear FEL. For a cold beam, at fixed output frequency, the growth rate in the strong pump regime is larger, by a factor of gamma2/3, in the circular FEL. The negative mass instability is shown to increase the growth rate and modify the bandwidth of the circular FEL in the strong pump regime. However, the circular FEL performance is found to be more sensitive to the energy spread than the linear FEL.
    BibTeX:
    @article{saito:2209,
      author = {H. Saito and J. S. Wurtele},
      title = {The linear theory of the circular free-electron laser},
      journal = {Physics of Fluids},
      publisher = {AIP},
      year = {1987},
      volume = {30},
      number = {7},
      pages = {2209-2220},
      url = {http://link.aip.org/link/?PFL/30/2209/1},
      doi = {http://dx.doi.org/10.1063/1.866155}
    }
    					
    E. T. Scharlemann, A. M. Sessler & J. S. Wurtele Optical Guiding in a Free-Electron Laser 1985 Phys. Rev. Lett.
    Vol. 54 (17), pp. 1925-1928  
    Abstract: By use of two-dimensional approximations for the equations that describe a high-gain free-electron laser (FEL) amplifier, and the properties of optical fibers, it is shown that the coherent interaction between the light and the electron beam in an FEL can optically guide the light. In the exponential-gain regime, the FEL performance in the presence of strong diffraction can be simply described by a cubic equation for the complex gain and the dispersion relation for an optical fiber. The phenomenon of optical guiding is illustrated with two-dimensional numerical simulations. The phenomenon has applications to short-wavelength FEL's, to directing of intense light, and to bending of x rays.
    BibTeX:
    @article{PhysRevLett.54.1925,
      author = {Scharlemann, E. T. and Sessler, A. M. and Wurtele, J. S.},
      title = {Optical Guiding in a Free-Electron Laser},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1985},
      volume = {54},
      number = {17},
      pages = {1925--1928},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.54.1925}
    }
    					
    C. B. Schroeder, D. H. Whittum & J. S. Wurtele Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator 1999 Phys. Rev. Lett.
    Vol. 82 (6), pp. 1177-1180  
    Abstract: The hollow plasma channel is analyzed as an accelerating structure. The excitation of the channel by an ultrarelativistic beam is analyzed. Coupling to the fundamental and all higher-order azimuthal modes of the excited electromagnetic fields is derived. Implications of this work for plasma-based accelerators, including beam loading and beam breakup, are discussed. Small initial transverse displacements of the beam are shown to couple to deflecting modes in the channel. The asymptotic growth rate of the resultant beam breakup instability is analyzed and a method for reducing the growth is proposed.
    BibTeX:
    @article{PhysRevLett.82.1177,
      author = {Schroeder, C. B. and Whittum, D. H. and Wurtele, J. S.},
      title = {Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1999},
      volume = {82},
      number = {6},
      pages = {1177--1180},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.82.1177}
    }
    					
    C. B. Schroeder & J. S. Wurtele P. L. Colestock & S. Kelley (Hrsg.) Particle beam stability in the hollow plasma channel wake field accelerator 2001 The ninth workshop on advanced accelerator concepts
    Vol. 569 (1), pp. 616-629  
    Abstract: The electromagnetic wake field response of a hollow plasma channel to a driver (laser or charged particle beam) of arbitrary velocity is derived. The dispersion and loss factors of excited fundamental and higher order azimuthal modes are computed. Growth rates for beam breakup instabilities are calculated and beam transport is studied. External focusing is shown to provide a method of controlling transverse instabilities. For parameters of interest for high gradient plasma-based accelerators, it is shown that the most severe limitation to the interaction length of a single accelerator stage based on the hollow plasma channel structure is the transverse instability of the particle beam.
    BibTeX:
    @conference{schroeder:616,
      author = {Carl B. Schroeder and Jonathan S. Wurtele},
      title = {Particle beam stability in the hollow plasma channel wake field accelerator},
      journal = {The ninth workshop on advanced accelerator concepts},
      publisher = {AIP},
      year = {2001},
      volume = {569},
      number = {1},
      pages = {616-629},
      url = {http://link.aip.org/link/?APC/569/616/1},
      doi = {http://dx.doi.org/10.1063/1.1384389}
    }
    					
    B. A. Shadwick & J. S. Wurtele General moment model of beam transport 1999 Particle Accelerator Conference, 1999. Proceedings of the 1999
    Vol. 4, pp. 2888-2890  
    Abstract: Using the Hamiltonian structure of the Vlasov equation, we develop a general, relativistic, three-dimensional model of beam transport based on phase space moments of the beam particle distribution. Evolution equations for these moments are derived from the non-canonical Poisson bracket for the Vlasov equation. In this model, the beam centroid experiences the full non-linear forces in the system while the higher order moments are coupled to both the centroid and to various spatial derivatives of the applied fields. For example, when moments up to second order are retained, the physics content is similar to considering linearized forces. Given the large number of equations (there are 27 equations when all second order moments are kept) and their algebraic complexity, the use of symbolic computation in the derivation was critical to ensuring the correctness of the equations. This approach also allows for analytical verification of conservation laws associated with the model. The initial investigations have considered only externally applied fields, however in principle space-charge forces can also be included. We discuss the necessary extensions to the basic theory needed to model ionization cooling for the muon collider
    BibTeX:
    @article{792972,
      author = {Shadwick, B. A. and Wurtele, J. S.},
      title = {General moment model of beam transport},
      journal = {Particle Accelerator Conference, 1999. Proceedings of the 1999},
      year = {1999},
      volume = {4},
      pages = {2888-2890},
      doi = {http://dx.doi.org/10.1109/PAC.1999.792972}
    }
    					
    B. A. Shadwick & J. S. Wurtele Numerical Studies of Wake Excitation in Plasma Channels 1998 (MOP21H)  
    Abstract: The wake fields produced by an intense, short laser pulse propagating in a plasma channel with an arbitrary density profile are investigated. Plasma channels, viewed as accelerating structures, have many desirable features that are not shared by a homogeneous plasma. Moreover, they are becoming experimentally realizable. As part of an overall program to analyze plasma channels as accelerating structures, a new fluid simulation code has been developed with the primary purpose of producing fast tools to explore parameter space for both theoretical investigation of accelerator performance as well as the modeling and design of experiments. This code has flexible physics content, for example, the lase can either be fully resolved temporally or treated as ponderomotive force. An important feature, from the accelerator design point of view, is the capability to study beam propagation dynamics. We present preliminary results consisting of a detailed analysis of the transverse structure of the wake for a wide range of channel profiles.
    BibTeX:
    @conference{Shadwick:MOP21H,
      author = {B. A. Shadwick and J. S. Wurtele},
      title = {Numerical Studies of Wake Excitation in Plasma Channels},
      year = {1998},
      number = {MOP21H},
      note = {Contributed to European Particle Accelerator Conference (EPAC 98), Stockholm, Sweden, 22-26 Jun 1998}
    }
    					
    B. A. Shadwickt, J. S. Wurtele, A. M. Sessler, C. M. Celata & P. B. Lee Modeling the muon cooling channel using moments 1999 Particle Accelerator Conference, 1999. Proceedings of the 1999
    Vol. 3, pp. 1716-1718  
    Abstract: Using a moment formalism, we model beam transport in the muon collider cooling channel. This model contains much of the physics we believe to be relevant to muon cooling such as ionization energy loss and multiple scattering. Space-charge forces are currently neglected but can, in principle, be added to the model. Previously, this model has been shown to closely agree with particle tracking while being significantly less computationally intensive. Presently our simulation is limited to the six-dimensional dynamics of the transverse cooling section. A matrix representation of an emittance exchange section is presented. This formulation of emittance exchange can either be ideal (conserving 6-d emittance) or can include energy loss and heating representative of the effects expected in a realistic emittance exchange section. These elements should give our model sufficient generality to enable the preliminary, yet realistic, design of a complete muon cooling channel
    BibTeX:
    @article{794232,
      author = {Shadwickt, B. A. and Wurtele, J. S. and Sessler, A. M. and Celata, C. M. and Lee, P. B.},
      title = {Modeling the muon cooling channel using moments},
      journal = {Particle Accelerator Conference, 1999. Proceedings of the 1999},
      year = {1999},
      volume = {3},
      pages = {1716-1718},
      doi = {http://dx.doi.org/10.1109/PAC.1999.794232}
    }
    					
    G. Shvets & J. S. Wurtele Transparency of Magnetized Plasma at the Cyclotron Frequency 2002 Phys. Rev. Lett.
    Vol. 89 (11), pp. 115003  
    Abstract: Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator, or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of nonlocal plasma oscillation. A Lagrangian description was used to elucidate the physics of the plasma transparency and control of group and phase velocity. This control leads to applications for electromagnetic pulse compression and electron/ion acceleration.
    BibTeX:
    @article{PhysRevLett.89.115003,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Transparency of Magnetized Plasma at the Cyclotron Frequency},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {2002},
      volume = {89},
      number = {11},
      pages = {115003},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.89.115003}
    }
    					
    G. Shvets & J. S. Wurtele Generation of ultrashort radiation pulses by injection locking a regenerative free-electron-laser amplifier 1997 Phys. Rev. E
    Vol. 56 (3), pp. 3606-3610  
    Abstract: We demonstrate how a steady-state train of ultrashort radiation pulses can be produced utilizing a new free-electron laser (FEL) configuration, the injection-locked regenerative klystron amplifier (IRKA). This configuration consists of two elements: (1) a prebuncher, which microbunches the electron beams at the desired output wavelength, and (2) a multipass FEL operated at a very small cavity desynchronism and below the lasing threshold, in the regime of regenerative amplification. The regenerative amplifier is driven by the microbunched electron beam, so that the pulse-to-pulse stability is provided by the pre-buncher. The broad amplification bandwidth of this regenerative amplifier enables generation of ultrashort pulses, much shorter than a slippage length, with high efficiency. The IRKA configuration can produce such ultra-short radiation pulses while avoiding the chaotic dynamics that limits conventional FEL performance.
    BibTeX:
    @article{PhysRevE.56.3606,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Generation of ultrashort radiation pulses by injection locking a regenerative free-electron-laser amplifier},
      journal = {Phys. Rev. E},
      publisher = {American Physical Society},
      year = {1997},
      volume = {56},
      number = {3},
      pages = {3606--3610},
      doi = {http://dx.doi.org/10.1103/PhysRevE.56.3606}
    }
    					
    G. Shvets & J. S. Wurtele SASE in plasmas: Analysis and simulation of Raman backscatter from noise 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 393 (1-3), pp. 371-375  
    Abstract: Theoretical techniques from free-electron laser research are modified for analytical and numerical investigations of Raman Backscatter (RBS) in plasmas. The physical system consists of an intense short laser pulse propagating through an underdense plasma. The analogy with the free-electron laser is essentially a correspondence of the plasma electrons with the electron beam, the incident laser pulse with the wiggler and the backscatter pulse with the radiation. This approach has significant advantages over previous theoretical treatments, which were mostly linear fluid theories, and particle-in-cell simulations which are computationally expensive. The problem of backscatter from noise, which is the RBS equivalent of SASE, is analyzed and compared to experimental observations.
    BibTeX:
    @article{Shvets:1997db,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {SASE in plasmas: Analysis and simulation of Raman backscatter from noise},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {393},
      number = {1-3},
      pages = {371--375},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPTFJX-81/1/f7150953fe83b620057629cc6031e22f}
    }
    					
    G. Shvets & J. S. Wurtele Pulse-shaping in short-pulse FEL oscillators using multiple resonators 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 393 (1-3), pp. 237-241  
    Abstract: A novel method is proposed for the efficient production of optical pulses that are shorter than a slippage length. The concept uses short electron bunches and a multiple cavity FEL oscillator configuration.
    BibTeX:
    @article{Shvets:1997eu,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Pulse-shaping in short-pulse FEL oscillators using multiple resonators},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {393},
      number = {1-3},
      pages = {237--241},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPTFJX-70/1/bc77b4832ec2f099b917086886dc7e79}
    }
    					
    G. Shvets & J. S. Wurtele Temporal and spectral structure of an FEL oscillator during start-up 1997 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 393 (1-3), pp. 273-276  
    Abstract: A previously developed Green's function technique for analyzing the time evolution of low-gain FEL oscillators is applied to the study of the start-up of oscillators from random beam noise. These calculations describe the evolution of the total radiation power and the spectral power as a function of pass number. The theory suggests that an estimate of the linear gain of an oscillator during start-up, as well as the noise level on the electron beam, can be inferred from a measurement of the position of the spectral peak of the FEL output. Analytical results are obtained for electron beams much longer than the slippage distance. A computationally efficient method for the spectral analysis of finite pulse FEL oscillators is described.
    BibTeX:
    @article{Shvets:1997lq,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Temporal and spectral structure of an FEL oscillator during start-up},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1997},
      volume = {393},
      number = {1-3},
      pages = {273--276},
      url = {http://www.sciencedirect.com/science/article/B6TJM-3SPTFJX-78/1/0a057280ead7eebf4058b20d06ecb697}
    }
    					
    G. Shvets & J. S. Wurtele Green function analysis of a Raman FEL 1995 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 358 (1-3), pp. 147-150  
    Abstract: This paper derives, in closed form, the Green function of an FEL operating in the strongly Raman regime. This Green function allows for the calculation of the temporal and spacial evolution of an arbitrary input radiation pulse. For the first time superradiance, originally studied in Compton regime by Bonifacio and co-workers [Phys. Rev. Lett. 73 (1994) 70; Nucl. Instr. and Meth. A 239 (1985) 36], has been seen numerically in a strongly Raman FEL.
    BibTeX:
    @article{Shvets:1995kx,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Green function analysis of a Raman FEL},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {1995},
      volume = {358},
      number = {1-3},
      pages = {147--150},
      url = {http://www.sciencedirect.com/science/article/B6TJM-497C66C-1K/1/a81074600cbd9e86338944dc35500e83}
    }
    					
    G. Shvets & J. S. Wurtele Green's Function Analysis of Free-electron Laser Amplifiers ;nd Oscillators 1994 Plasma Science, 1994. Conference Record - Abstracts., 1994 IEEE International Conference on, pp. 201-201  
    BibTeX:
    @article{589081,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Green's Function Analysis of Free-electron Laser Amplifiers ;nd Oscillators},
      journal = {Plasma Science, 1994. Conference Record - Abstracts., 1994 IEEE International Conference on},
      year = {1994},
      pages = {201-201}
    }
    					
    G. Shvets & J. S. Wurtele Instabilities of Short-Pulse Laser Propagation through Plasma Channels 1994 Phys. Rev. Lett.
    Vol. 73 (26), pp. 3540-3543  
    Abstract: The stability of short laser pulses propagating through plasma channels is investigated theoretically. Perturbations to the laser pulse are shown to modify the ponderomotive pressure, which distorts the dielectric properties of the plasma channel. The channel perturbation then further distorts the laser pulse. A set of coupled mode equations is derived, and a matrix dispersion relation is obtained analytically for the special case of a quadratic radial density variation. As an example, the spatiotemporal growth of a pure dipole perturbation is evaluated in various parameter regimes. Mechanisms for suppressing the instability are discussed.
    BibTeX:
    @article{PhysRevLett.73.3540,
      author = {Shvets, G. and Wurtele, J. S.},
      title = {Instabilities of Short-Pulse Laser Propagation through Plasma Channels},
      journal = {Phys. Rev. Lett.},
      publisher = {American Physical Society},
      year = {1994},
      volume = {73},
      number = {26},
      pages = {3540--3543},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.73.3540}
    }
    					
    G. Shvets & J. S. Wurtele Frequency shifting in free-electron lasers 1994 Phys. of Plasma
    Vol. 1 (1), pp. 157-166  
    Abstract: Frequency shifting in free-electron laser (FEL) oscillators and amplifiers is investigated theoretically and numerically. The analysis includes frequency shifts from the resonant FEL interaction and the nonresonant beam dielectric. Expressions for the frequency shift in a microwave amplifier with time-dependent beam energy and current are derived and found to be in good agreement with experiments. The theory shows that temporal changes in the detuning are the dominant factor in determining the frequency shift. Electron energy fluctuations produce frequency shifts in the Compton regime, while both current and energy variations are significant in the Raman regime. The effect is particularly important for high-power microwave drivers proposed for high gradient accelerators, where the phase of the radio-frequency radiation is subject to significant constraints. FEL oscillator response to variations in beam energy is examined. It is shown that in a low-gain oscillator which experiences a sudden jump in beam energy the FEL creates spikes at the head and tail of the beam which are at the shifted frequency. The shifting is generated by time dependence in dielectric function which arises from slippage and finite lengths of the electron or optical pulse. The propagation diffusion equation is shown to describe the propagation of the spikes into the main body of the pulse.
    BibTeX:
    @article{shvets:157,
      author = {G. Shvets and J. S. Wurtele},
      title = {Frequency shifting in free-electron lasers},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {1994},
      volume = {1},
      number = {1},
      pages = {157-166},
      url = {http://link.aip.org/link/?PHP/1/157/1},
      doi = {http://dx.doi.org/10.1063/1.870546}
    }
    					
    G. Shvets, J. S. Wurtele, T. C. Chiou & T. C. Katsouleas Excitation of accelerating wakefields in inhomogeneous plasmas 1996 Plasma Science, IEEE Transactions on
    Vol. 24 (2), pp. 351-362  
    Abstract: The excitation of the wakefields in an inhomogeneous plasma by a short laser pulse is investigated theoretically. A general equation for the wake excitation in transversely nonuniform plasma is derived. This equation is applied to the step-function density profile model of hollow channel laser wakefield accelerator. A more realistic model, in which the transition between the evacuated channel and the homogeneous surrounding plasma occurs over a finite radial extent, is then analyzed. It is shown that the excited channel made can interact resonantly with the plasma electrons inside the channel wall, leading to secular growth of the electric field. This eventually results in wavebreaking and the dissipation of the accelerating mode. We introduce an effective quality factor Q for the hollow channel laser wakefield geometry. This resonance limits the number of electron bunches that can be accelerated in the wake of single laser pulse
    BibTeX:
    @article{509999,
      author = {Shvets, G. and Wurtele, J. S. and Chiou, T. C. and Katsouleas, T. C.},
      title = {Excitation of accelerating wakefields in inhomogeneous plasmas},
      journal = {Plasma Science, IEEE Transactions on},
      year = {1996},
      volume = {24},
      number = {2},
      pages = {351-362},
      doi = {http://dx.doi.org/10.1109/27.509999}
    }
    					
    G. Shvets, J. S. Wurtele & M.-S. Hur Applications of Magnetized Plasma to Particle Acceleration 2002 Advanced Accelerator Concepts: Tenth Workshop
    Vol. 647 (1), pp. 681-689  
    Abstract: Magnetized plasma can be used as an accelerating structure capable of supporting large amplitude longitudinal fields which are externally driven by a high-frequency microwave source. Such structures can be used at very high frequencies (hundreds of gigahertz), placing them in the intermediate region between conventional (metallic) accelerators, and laser-driven plasma accelerators. We review two magnetic field configurations with respect to the direction of the particle beam propagation: (1) parallel magnetic field plus a helical undulator, and (2) perpendicular magnetic field. In the first configuration, plasma exhibits electromagnetically induced transparency (EIT) at the cyclotron frequency if the plasma frequency is equal to the electron cyclotron frequency. The second configuration corresponds to the inverse Cherenkov effect in magnetized plasma. In both cases, the group velocity of the accelerating plasma wave can be made very small, so that the incident electromagnetic wave is strongly compressed, resulting in the high accelerating gradient.
    BibTeX:
    @conference{shvets:681,
      author = {Gennady Shvets and Jonathan S. Wurtele and Min-Sup Hur},
      title = {Applications of Magnetized Plasma to Particle Acceleration},
      journal = {Advanced Accelerator Concepts: Tenth Workshop},
      publisher = {AIP},
      year = {2002},
      volume = {647},
      number = {1},
      pages = {681-689},
      url = {http://link.aip.org/link/?APC/647/681/1},
      doi = {http://dx.doi.org/10.1063/1.1524923}
    }
    					
    G. Shvets, J. S. Wurtele & B. A. Shadwick Analysis and simulation of Raman backscatter in underdense plasmas 1997 The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society
    Vol. 4 (5), pp. 1872-1880  
    Abstract: A new formalism to describe the spatiotemporal evolution of relativistic Raman backscatter (RBS) of ultrashort laser pulses in underdense plasma has been developed. This theory is based on an eikonal representation for the RBS field and averaging over the oscillation frequency. Equations are derived for the evolution of the RBS radiation field amplitude and phase and for particle motion in the ponderomotive potential of the pump and RBS fields. A technique similar to that used in Raman free electron lasers is used to include the plasma density oscillation and its electric field in the particle equations. The equations have been solved numerically in a code that provides an accurate description of the nonlinear electron motion on a short spatial scale of half the radiation wavelength, while at the same time evolving the laser field on a much coarser scale, characteristic of the growth rate of the instability. Two-dimensional nonlinear effects, such as the return current, are analytically estimated and phenomenologically incorporated in the numerical code. The results of recent (RBS) experiments are compared with the analytical and numerical predictions of the theory. A statistical theory of the linear RBS instability growing from plasma noise is developed. It is found that in the nonlinear regime backscattered radiation, seeded by random density fluctuations in the plasma, breaks up into spikes, which exhibit superradiant behavior. These effects might explain the spikiness of the RBS spectra in the nonlinear regime.
    BibTeX:
    @conference{shvets:1872,
      author = {G. Shvets and J. S. Wurtele and B. A. Shadwick},
      title = {Analysis and simulation of Raman backscatter in underdense plasmas},
      journal = {The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society},
      publisher = {AIP},
      year = {1997},
      volume = {4},
      number = {5},
      pages = {1872-1880},
      url = {http://link.aip.org/link/?PHP/4/1872/1},
      doi = {http://dx.doi.org/10.1063/1.872330}
    }
    					
    P. L. Similon & J. S. Wurtele Depletion and diffraction of an electromagnetic wiggler field during the free electron laser interaction 1989 Physics of Fluids B: Plasma Physics
    Vol. 1 (6), pp. 1307-1315  
    Abstract: The self-consistent interaction of an electron beam with an electromagnetic wiggler and a radiation field is analyzed. Equations are derived for the depletion and diffraction of the wiggler wave. The formalism yields local conservation laws for the system energy flux and photon flux. Using a one-dimensional approximation, pump depletion is examined for pulsed and steady-state electron beams. A three-dimensional analysis shows that the wiggler diffraction is dominated by the nonresonant interaction of the electrons with the wiggler wave. This is studied in detail for a specific electron pulse shape. It is concluded that wiggler depletion and diffraction should not substantially degrade the free electron laser interaction for experimentally obtainable system parameters.
    BibTeX:
    @article{similon:1307,
      author = {P. L. Similon and J. S. Wurtele},
      title = {Depletion and diffraction of an electromagnetic wiggler field during the free electron laser interaction},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1989},
      volume = {1},
      number = {6},
      pages = {1307-1315},
      url = {http://link.aip.org/link/?PFB/1/1307/1},
      doi = {http://dx.doi.org/10.1063/1.858955}
    }
    					
    P. H. Stoltz, J. R. Cary, G. Penn & J. S. Wurtele Efficiency of a Boris-like integration scheme with spatial stepping 2002 Phys. Rev. ST Accel. Beams
    Vol. 5 (9), pp. 094001  
    Abstract: A modified Boris-like integration, in which the spatial coordinate is the independent variable, is derived. This spatial-Boris integration method is useful for beam simulations, in which the independent variable is often the distance along the beam. The new integration method is second order accurate, requires only one force calculation per particle per step, and preserves conserved quantities more accurately over long distances than a Runge-Kutta integration scheme. Results from the spatial-Boris integration method and a Runge-Kutta scheme are compared for two simulations: (i) a particle in a uniform solenoid field and (ii) a particle in a sinusoidally varying solenoid field. In the uniform solenoid case, the spatial-Boris scheme is shown to perfectly conserve for any step size quantities such as the gyroradius and the perpendicular momentum. The Runge-Kutta integrator produces damping in these conserved quantities. In the sinusoidally varying case, the conserved quantity of canonical angular momentum is used to measure the accuracy of the two schemes. For the sinusoidally varying field simulations, error analysis is used to determine the integration distance beyond which the spatial-Boris integration method is more efficient than a fourth-order Runge-Kutta scheme. For beam physics applications where statistical quantities such as beam emittance are important, these results imply the spatial-Boris scheme is 3 times more efficient.
    BibTeX:
    @article{PhysRevSTAB.5.094001,
      author = {Stoltz, P. H. and Cary, J. R. and Penn, G. and Wurtele, J. S.},
      title = {Efficiency of a Boris-like integration scheme with spatial stepping},
      journal = {Phys. Rev. ST Accel. Beams},
      publisher = {American Physical Society},
      year = {2002},
      volume = {5},
      number = {9},
      pages = {094001},
      doi = {http://dx.doi.org/10.1103/PhysRevSTAB.5.094001}
    }
    					
    T. Tran, B. Danly & J. S. Wurtele Free-electron lasers with electromagnetic standing wave wigglers 1987 Quantum Electronics, IEEE Journal of
    Vol. 23 (9), pp. 1578-1589  
    Abstract: A detailed analysis of the electromagnetic standing wave wiggler for free-electron lasers (FEL's) is conducted for both circular and linear wiggler polarizations, following a single-particle approach. After determination of the unperturbed electron orbits in the wiggler field, the single-particle spontaneous emission spectrum and subsequently the gain in the low gain Compton regime (using the Einstein coefficient method) are explicitly calculated. This analysis results in a clear understanding of the resonance conditions and the coupling strength associated with each resonance of this type of FEL. In particular, a striking feature obtained from this investigation is that the electromagnetic standing wave wiggler FEL, under certain circumstances, exhibits a rich harmonic content. This harmonic content is caused by the presence of both the forward and backward wave components of the standing wave wiggler field. In addition, the nonlinear self-consistent equations for this type of FEL are also presented, permitting further investigation of it by the theoretical techniques and numerical codes developed for conventional FEL's.
    BibTeX:
    @article{1073537,
      author = {Tran, T. and Danly, B. and Wurtele, J. S.},
      title = {Free-electron lasers with electromagnetic standing wave wigglers},
      journal = {Quantum Electronics, IEEE Journal of},
      year = {1987},
      volume = {23},
      number = {9},
      pages = {1578-1589}
    }
    					
    P. Volfbeyn, P. B. Lee, J. S. Wurtele, W. P. Leemans & G. Shvets Driving laser pulse evolution in a laser wakefield accelerator 1997 Particle Accelerator Conference, 1997. Proceedings of the 1997
    Vol. 1, pp. 657-659  
    Abstract: A numerical study of the coupling between a high intensity laser pulse and a plasma wake is presented, in the context of laser wakefield acceleration in a hollow channel. One dimensional self-consistent equations are derived and numerically solved to provide a more detailed description of the laser pulse evolution for the case of propagation in a uniform plasma. The model obtained provides a simple method for inferring the plasma wake characteristics from measurement of changes in phase and amplitude of the driving laser pulse
    BibTeX:
    @article{749796,
      author = {Volfbeyn, P. and Lee, P. B. and Wurtele, J. S. and Leemans, W. P. and Shvets, G.},
      title = {Driving laser pulse evolution in a laser wakefield accelerator},
      journal = {Particle Accelerator Conference, 1997. Proceedings of the 1997},
      year = {1997},
      volume = {1},
      pages = {657-659},
      doi = {http://dx.doi.org/10.1109/PAC.1997.749796}
    }
    					
    P. Volfbeyn, P. B. Lee, J. S. Wurtele, W. P. Leemans & G. Shvets Driving laser pulse evolution in a hollow channel laser wakefield accelerator 1997 Phys. of Plasma
    Vol. 4 (9), pp. 3403-3410  
    Abstract: An analytic and numerical study of the coupling between a high-intensity laser pulse and a plasma wake is presented, in the context of laser wakefield acceleration in a hollow channel. Laser wavelength reddening and pulse length shortening are qualitatively described using simple scaling laws. One-dimensional self-consistent equations are derived and numerically solved to provide a more detailed description of the laser pulse evolution for the case of propagation in a uniform plasma. These equations are extended to treat the case of laser pulse propagation in a hollow channel. The coupling between the plasma and the laser pulse is calculated using energy conservation. The model obtained provides a simple method for inferring the plasma wake characteristics from measurement of changes in phase and amplitude of the driving laser pulse.
    BibTeX:
    @article{volfbeyn:3403,
      author = {P. Volfbeyn and P. B. Lee and J. S. Wurtele and W. P. Leemans and G. Shvets},
      title = {Driving laser pulse evolution in a hollow channel laser wakefield accelerator},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {1997},
      volume = {4},
      number = {9},
      pages = {3403-3410},
      url = {http://link.aip.org/link/?PHP/4/3403/1},
      doi = {http://dx.doi.org/10.1063/1.872482}
    }
    					
    W. Fawley, G. Penn, A. Sessler & J. S. Wurtele Studies of the Front End of a Neutrino Factory 2001 (FOAC011)  
    Abstract: A neutrino factory employs muons which are produced, collected, colled, accelerated and then stored so that their eventual decay produces an intense neutrino beam. A general description may be be found in the paper by Geer [S. Geer, Phys. Rev. D, 57, 1 (1998)], and two upcoming Comments on Nuclear and Particle Physics articles [S. Geer, "Future prospects for muon facilities", http://www-mucool.fnal.gov/mcnotes/muc0155.pdf]. In this contribution, we use analytic and numerical tools to investigate the performance of the front end of a neutino factory. This region starts just after the target and ends just prior to the recirculating accelerators. Extensive previous work has resulted in the designs used in the Fermilab Study of 1999-2000 and the Brookhaven Study of 2000-2001. Here we explore variations away from the particulare designs, seeking possible improvements in the final muon output, risk reduction, and ultime cost. Our studies include changes in the overall front end geometry through optimizations of the induction linac design and variations of the rf frequency in the cooling channel accerlation, and initial exploration of the use of helical wiggler fields to increase the range of initial muon energies that are captured.
    BibTeX:
    @conference{Fawley:FOAC011,
      author = {W. Fawley, and G. Penn, and A. Sessler, and J. S. Wurtele},
      title = {Studies of the Front End of a Neutrino Factory},
      year = {2001},
      number = {FOAC011},
      note = {Proceedings of 2001 Particle Accelerator Conference, Chicago}
    }
    					
    W.P. Leemans, D. Rodgers, P.E. Catravas, G. Fubiani, C.G.R. Geddes, E. Esarey, B.A. Shadwick, J. van Tilborg, S. Chattopadhyay, J.S. Wurtele, L. Archambault, M.R. Dickinson, S. DiMaggio, R. Short, K.L. Barat, R. Donahue, J. Floyd, A. Smith & E. Wong All-Optical Accelerator Experiments at LBNL 2000 (TH201)  
    BibTeX:
    @conference{Leemans:TH201,
      author = {W.P. Leemans, and D. Rodgers, and P.E. Catravas, and G. Fubiani, and C.G.R. Geddes, and E. Esarey, and B.A. Shadwick, and J. van Tilborg, and S. Chattopadhyay, and J.S. Wurtele, and L. Archambault, and M.R. Dickinson, and S. DiMaggio, and R. Short, and K.L. Barat, and R. Donahue, and J. Floyd, and A. Smith, and E. Wong},
      title = {All-Optical Accelerator Experiments at LBNL},
      year = {2000},
      number = {TH201}
    }
    					
    T.-L. Wang, D. Michta, R. R. Lindberg, A. E. Charman, S. F. Martins & J. S. Wurtele Feasibility study for using an extended three-wave model to simulate plasma-based backward Raman amplification in one spatial dimension 2009 Physics of Plasmas
    Vol. 16 (12), pp. 123110  
    Abstract: Results are reported of a one-dimensional simulation study comparing the modeling capability of a recently formulated extended three-wave model [ R. R. Lindberg, A. E. Charman, and J. S. Wurtele, Phys. Plasmas 14, 122103 (2007) ; Phys. Plasmas 15, 055911 (2008) ] to that of a particle-in-cell (PIC) code, as well as to a more conventional three-wave model, in the context of the plasma-based backward Raman amplification (PBRA) [ G. Shvets, N. J. Fisch, A. Pukhov et al., Phys. Rev. Lett. 81, 4879 (1998) ; V. M. Malkin, G. Shvets, and N. J. Fisch, Phys. Rev. Lett. 82, 4448 (1999) ; Phys. Rev. Lett. 84, 1208 (2000) ]. The extended three-wave model performs essentially as well as or better than a conventional three-wave description in all temperature regimes tested, and significantly better at the higher temperatures studied, while the computational savings afforded by the extended three-wave model make it a potentially attractive tool that can be used prior to or in conjunction with PIC simulations to model the kinetic effects of PBRA for nonrelativistic laser pulses interacting with underdense thermal plasmas. Very fast but reasonably accurate at moderate plasma temperatures, this model may be used to perform wide-ranging parameter scans or other exploratory analyses quickly and efficiently, in order to guide subsequent simulation via more accurate if intensive PIC techniques or other algorithms approximating the full Vlasov?Maxwell equations.
    BibTeX:
    @article{Wang2009,
      author = {T.-L. Wang and D. Michta and R. R. Lindberg and A. E. Charman and S. F. Martins and J. S. Wurtele},
      title = {Feasibility study for using an extended three-wave model to simulate plasma-based backward Raman amplification in one spatial dimension},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2009},
      volume = {16},
      number = {12},
      pages = {123110},
      url = {http://link.aip.org/link/?PHP/16/123110/1},
      doi = {http://dx.doi.org/10.1063/1.3280012}
    }
    					
    Wen-Hao Cheng, Andrew M. Sessler & J. S. Wurtele Single Bunch Collective effects in Muon Colliders 1996 (WEP078G)  
    Abstract: Theoretical examination is made of single bunch collective effects in the collider ring of a 2 Tev x 2 Tev Mu-Mu Collider complex. The situation involves an intense bunch, a short bunch, a small momentum compaction, a rather large impedance for the rf system, and luminosity life time limited by muon decay to of the order a thousand turns. The use in rings of techniques such as BNS damping, developed for linear colliders, is discussed. Qualitative descriptions and numerical simulation results are presented.
    BibTeX:
    @conference{Cheng:WEP078G,
      author = {Wen-Hao Cheng, and Andrew M. Sessler, and Jonathan S. Wurtele},
      title = {Single Bunch Collective effects in Muon Colliders},
      year = {1996},
      number = {WEP078G},
      note = {Contributed to European Particle Accelerator Conference (EPAC 96), Barcelona, Spain, 10-14 Jun 1996}
    }
    					
    S. G. Wojcicki & J. S. Wurtele NuFact00 workshop summary 2001 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Vol. 472 (3), pp. 323-328  
    Abstract: A brief summary of the workshop is presented.
    BibTeX:
    @article{Wojcicki:2001vn,
      author = {Wojcicki, Stanley G. and Wurtele, Jonathan S.},
      title = {NuFact00 workshop summary},
      journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
      year = {2001},
      volume = {472},
      number = {3},
      pages = {323--328},
      url = {http://www.sciencedirect.com/science/article/B6TJM-448YPDG-3/1/90782dbb0fa525d637fd4034b18f2ecb}
    }
    					
    A. Wolski, G. Penn, A. Sessler & J. S. Wurtele Beam conditioning for free electron lasers: Consequences and methods 2004 Phys. Rev. ST Accel. Beams
    Vol. 7 (8), pp. 080701  
    Abstract: The consequences of beam conditioning in four example cases [VISA, a soft x-ray free-electron laser (FEL), LCLS, and a ``Greenfield'' FEL] are examined. It is shown that in emittance limited cases, proper conditioning reduces sensitivity to the transverse emittance and, furthermore, allows for stronger focusing in the undulator. Simulations show higher saturation power, with gain lengths reduced by a factor of 2 or more. The beam dynamics in a general conditioning system are studied, with ``matching conditions'' derived for achieving conditioning without growth in the effective emittance. Various conditioning lattices are considered, and expressions derived for the amount of conditioning provided in each case when the matching conditions are satisfied. These results show that there is no fundamental obstacle to producing beam conditioning, and that the problem can be reduced to one of proper lattice design. Nevertheless, beam conditioning will not be easy to implement in practice.
    BibTeX:
    @article{PhysRevSTAB.7.080701,
      author = {Wolski, A. and Penn, G. and Sessler, A. and Wurtele, J. S.},
      title = {Beam conditioning for free electron lasers: Consequences and methods},
      journal = {Phys. Rev. ST Accel. Beams},
      publisher = {American Physical Society},
      year = {2004},
      volume = {7},
      number = {8},
      pages = {080701},
      doi = {http://dx.doi.org/10.1103/PhysRevSTAB.7.080701}
    }
    					
    J. Wurtele, K.-J. Kim, R. R. Lindberg, A. Zholents, G. Penn, M. Reinsch, P. R. Gandhi & X.-W. Gu Tunable Soft X-ray Oscillators 2010  
    BibTeX:
    @conference{,
      author = {J. Wurtele and K.-J. Kim and R. R. Lindberg and A. Zholents and G. Penn and M. Reinsch and Punit R. Gandhi and Xiao-Wei Gu},
      title = {Tunable Soft X-ray Oscillators},
      booktitle = {Proceedings of the 2010 Free Electron Laser Conference},
      year = {2010}
    }
    					
    J. S. Wurtele Towards Very High Energy Accelerators 2000 International Journal of Modern Physics A
    Vol. 15 (1b supp), pp. 816-839  
    BibTeX:
    @article{Wurtele,
      author = {Wurtele, J. S.},
      title = {Towards Very High Energy Accelerators},
      journal = {International Journal of Modern Physics A},
      year = {2000},
      volume = {15},
      number = {1b supp},
      pages = {816-839},
      doi = {http://dx.doi.org/10.1142/S0217751X00005437}
    }
    					
    J. S. Wurtele The role of plasma in advanced accelerators@f| 1993 Physics of Fluids B: Plasma Physics
    Vol. 5 (7), pp. 2363-2370  
    Abstract: The role of plasma in advanced accelerators is reviewed with emphasis on three significant areas of research: plasma guiding of beams in accelerators, plasma focusing of beams in high-energy linear colliders, and plasma acceleration of beams.
    BibTeX:
    @article{wurtele:2363,
      author = {Jonathan S. Wurtele},
      title = {The role of plasma in advanced accelerators@f|},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1993},
      volume = {5},
      number = {7},
      pages = {2363-2370},
      url = {http://link.aip.org/link/?PFB/5/2363/1},
      doi = {http://dx.doi.org/10.1063/1.860719}
    }
    					
    A. I. Zhmoginov, A. E. Charman, R. Shalloo, J. Fajans and J. S. Wurtele. Nonlinear dynamics of anti-hydrogen in magnetostatic traps: implications for gravitational measurements 2013 Classical and Quantum Gravity
    Vol. 30 (20), p. 205014  
    BibTeX:
    						@article{Zhmoginov:13,
    						  author = {Zhmoginov, A. I. and Charman, A. E. and Shalloo, R. and Fajans, J. and Wurtele, J. S.},
    						  title = {Nonlinear dynamics of anti-hydrogen in magnetostatic traps: implications for gravitational measurements},
    						  journal = {Classical and Quantum Gravity},
    						  year = {2013},
    						  volume = {30},
    						  number = {20},
    						  pages = {205014},
    						  doi = {10.1088/0264-9381/30/20/205014}
    						}
    					
    C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, E. Butler, A. Capra, C. L. Cesar, M. Charlton, A. Deller, P. H. Donnan, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, A. J. Humphries, C. A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, C. R. Shields, D. M. Silveira,S. Stracka, C. So, R. I. Thompson, D. P. van der Werf and J. S. Wurtele Resonant quantum transitions in trapped antihydrogen atoms 2012 Nature
    Vol. 483, p. 439  
    BibTeX:
    						@article{amole:12a,
    							author = {Amole, C. and Ashkezari, M.D. and Baquero-Ruiz, M. and Bertsche, W. and Bowe, P.D. and Butler, E. and Capra, A. and Cesar, C.L. and Charlton, M. and Deller, A. and Donnan, P.H. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M.C. and Gill, D.R. and Gutierrez, A. and Hangst, J.S. and Hardy, W.N. and Hayden, M.E. and Humphries, A.J. and Isaac, C.A. and Jonsell, S. and Kurchaninov, L. and Little, A. and Madsen, N. and McKenna, J.T.K. and Menary, S. and Napoli, S.C. and Nolan, P. and Olchanski, K. and Olin, A. and Pusa, P. and Rasmussen, C.O. and Robicheaux, F. and Sarid, E. and Shields, C.R. and Silveira, D.M. and Stracka, S. and So, C. and Thompson, R.I. and Van Der Werf, D.P. and Wurtele, J.S.},
    							title = {Resonant quantum transitions in trapped antihydrogen atoms},
    							journal = {Nature},
    							year = {2012},
    							volume = {483},
    							pages = {439},
    							url = {http://www.nature.com/nature/journal/v483/n7390/full/nature10942.html}
    						}
    					
    C Amole, G B Andresen, M D Ashkezari, M Baquero-Ruiz, W Bertsche, E Butler, C L Cesar, S Chapman, M Charlton, A Deller, S Eriksson, J Fajans, T Friesen, M C Fujiwara, D R Gill, A Gutierrez, J S Hangst, W N Hardy, M E Hayden, A J Humphries, R Hydomako, L Kurchaninov, S Jonsell, N Madsen, S Menary, P Nolan, K Olchanski, A Olin, A Povilus, P Pusa, F Robicheaux, E Sarid, D M Silveira, C So, J W Storey, R I Thompson, D P van der Werf, and J S Wurtele Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap 2012 New J. Phys.
    Vol. 14, p. 015010  
    BibTeX:
    						@article{amole:12b,
    							author = {C Amole and G B Andresen and M D Ashkezari and M Baquero-Ruiz and W Bertsche and E Butler and C L Cesar and S Chapman and M
    							Charlton and A Deller and S Eriksson and J Fajans and T Friesen and M C Fujiwara and D R Gill and A Gutierrez and J S Hangst and W N
    							Hardy and M E Hayden and A J Humphries and R Hydomako and L Kurchaninov and S Jonsell and N Madsen and S Menary and P Nolan and K
    							Olchanski and A Olin and A Povilus and P Pusa and F Robicheaux and E Sarid and D M Silveira and C So and J W Storey and R I Thompson and D P
    							van der Werf and J S Wurtele},
    							title = {Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap},
    							journal = {New Journal of Physics},
    							volume = {14},
    							number = {1},
    							pages = {015010},
    							year = {2012},
    							doi = {10.1088/1367-2630/14/1/015010}
    						}
    					
    C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. L. Cesar, M. Charlton, A. Deller, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, C. R. Shields, D. M. Silveira, C. So, S. Stracka, R. I. Thompson, D. P. van der Werf, J. S. Wurtele, A. Zhmoginov, (ALPHA collaboration) and L. Friedland Experimental and computational study of the injection of antiprotons into a positron plasma for antihydrogen production 2013 Phys. Plasmas
    Vol. 20, p. 043510  
    BibTeX:
    						@article{amole:13a,
    							author = {Amole, C. and Ashkezari, M. D. and Baquero-Ruiz, M. and Bertsche, W. and Butler, E. and Capra, A. and Cesar, C. L. and Charlton, M. and Deller, A. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M. C. and Gill, D. R. and Gutierrez, A. and Hangst, J. S. and Hardy, W. N. and Hayden, M. E. and Isaac, C. A. and Jonsell, S. and Kurchaninov, L. and Little, A. and Madsen, N. and McKenna, J. T. K. and Menary, S. and Napoli, S. C. and Olchanski, K. and Olin, A. and Pusa, P. and Rasmussen, C. O. and Robicheaux, F. and Sarid, E. and Shields, C. R. and Silveira, D. M. and So, C. and Stracka, S. and Thompson, R. I. and van der Werf, D. P. and Wurtele, J. S. and Zhmoginov, A. and (ALPHA collaboration) and Friedland, L.},
       							title = {Experimental and computational study of the injection of antiprotons into a positron plasma for antihydrogen production},
       							journal = {Physics of Plasmas (1994-present)},
       							year = {2013},
       							volume = {20},
       							number = {4},
    							doi = {10.1063/1.4801067}
    						}
    					
    C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. L. Cesar, M. Charlton, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, A. Olin, P. Pusa, C. Ø Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, R. I. Thompson, D. P. van der Werf, J. S. Wurtele, A. I. Zhmoginov and A. Charman Description and first application of a new technique to measure the gravitational mass of antihydrogen 2013 Nature Communications
    Vol. 4, art. no. 1785  
    BibTeX:
    						@article{amole:13b,
    							author = {Amole, C. and Ashkezari, M.D. and Baquero-Ruiz, M. and Bertsche, W. and Butler, E. and Capra, A. and Cesar, C.L. and Charlton, M. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M.C. and Gill, D.R. and Gutierrez, A. and Hangst, J.S. and Hardy, W.N. and Hayden, M.E. and Isaac, C.A. and Jonsell, S. and Kurchaninov, L. and Little, A. and Madsen, N. and McKenna, J.T.K. and Menary, S. and Napoli, S.C. and Nolan, P. and Olin, A. and Pusa, P. and Rasmussen, C. O. and Robicheaux, F. and Sarid, E. and Silveira, D.M. and So, C. and Thompson, R.I. and Van Der Werf, D.P. and Wurtele, J.S. and Zhmoginov, A.I. and Charman, A.E.},
    							title = {Description and first application of a new technique to measure the gravitational mass of antihydrogen},
    							journal = {Nature Communications},
    							year = {2013},
    							volume = {4},
    							art_number = {1785},
    							doi = {10.1038/ncomms2787}
    						}
    					
    P. Hamilton, A. Zhmoginov, F. Robicheaux, J. Fajans, J. S. Wurtele, and H. Müller Antimatter Interferometry for Gravity Measurements 2014 Phys. Rev. Lett.
    Vol. 112, p. 121102  
    BibTeX:
    						@article{hamilton:14,
    							title = {Antimatter Interferometry for Gravity Measurements},
    							author = {Hamilton, Paul and Zhmoginov, Andrey and Robicheaux, Francis and Fajans, Joel and Wurtele, Jonathan S. and M\"uller, Holger},
    							journal = {Phys. Rev. Lett.},
    							volume = {112},
    							issue = {12},
    							pages = {121102},
    							numpages = {5},
    							year = {2014},
    							month = {Mar},
    							publisher = {American Physical Society},
    							doi = {10.1103/PhysRevLett.112.121102}
    						}
    					
    C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. L. Cesar, M. Charlton, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, T. D. Tharp, R. I. Thompson, D. P. van der Werf, Z. Vendeiro, J. S. Wurtele, A. I. Zhmoginov and A. E. Charman An experimental limit on the charge of antihydrogen 2014 Nature Communications
    Vol. 5, art. no. 3955  
    BibTeX:
    						@article{amole:14a,
    							author = {Amole, C. and Ashkezari, M.D. and Baquero-Ruiz, M. and Bertsche, W. and Butler, E. and Capra, A. and Cesar, C.L. and Charlton, M. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M.C. and Gill, D.R. and Gutierrez, A. and Hangst, J.S. and Hardy, W.N. and Hayden, M.E. and Isaac, C.A. and Jonsell, S. and Kurchaninov, L. and Little, A. and Madsen, N. and McKenna, J.T.K. and Menary, S. and Napoli, S.C. and Nolan, P. and Olchanski, K. and Olin, A. and Povilus, A. and Pusa, P. and Rasmussen, C.. and Robicheaux, F. and Sarid, E. and Silveira, D.M. and So, C. and Tharp, T.D. and Thompson, R.I. and Van Der Werf, D.P. and Vendeiro, Z. and Wurtele, J.S. and Zhmoginov, A.I. and Charman, A.E.},
    							title={An experimental limit on the charge of antihydrogen},
    							journal={Nature Communications},
    							year={2014},
    							volume={5},
    							art_number={3955}
    						}
    					
    C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. L. Cesar, S. Chapman, M. Charlton, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, S. Stracka, C. So, R. I. Thompson, M. Turner, D. P. van der Werf, J. S. Wurtele, A. Zhmoginov and ALPHA Collaboration Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus 2013 Phys. Rev. Lett.
    Vol. 112, p. 121102  
    BibTeX:
    						@article{amole:13c,
    							author={Amole, C. and Ashkezari, M.D. and Baquero-Ruiz, M. and Bertsche, W. and Butler, E. and Capra, A. and Cesar, C.L. and Chapman, S. and Charlton, M. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M.C. and Gill, D.R. and Gutierrez, A. and Hangst, J.S. and Hardy, W.N. and Hayden, M.E. and Isaac, C.A. and Jonsell, S. and Kurchaninov, L. and Little, A. and Madsen, N. and McKenna, J.T.K. and Menary, S. and Napoli, S.C. and Nolan, P. and Olchanski, K. and Olin, A. and Povilus, A. and Pusa, P. and Rasmussen, C. and Robicheaux, F. and Sarid, E. and Silveira, D.M. and Stracka, S. and So, C. and Thompson, R.I. and Turner, M. and Van Der Werf, D.P. and Wurtele, J.S. and Zhmoginov, A.},
    							title={Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus},
    							journal={Review of Scientific Instruments},
    							year={2013},
    							volume={84},
    							number={6},
    							art_number={065110}
    						}
    					
    G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, E. Butler, C. L. Cesar, M. Charlton, A. Deller, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, S. Jonsell, S. L. Kemp, L. Kurchaninov, N. Madsen, S. Menary, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele and Y. Yamazaki Confinement of antihydrogen for 1,000 seconds 2011 Nature Physics
    Vol. 7, p. 558  
    BibTeX:
    						@article{andresen:11a,
    							author={Andresen, G.B. and Ashkezari, M.D. and Baquero-Ruiz, M. and Bertsche, W. and Bowe, P.D. and Butler, E. and Cesar, C.L. and Charlton, M. and Deller, A. and Eriksson, S. and Fajans, J. and Friesen, T. and Fujiwara, M.C. and Gill, D.R. and Gutierrez, A. and Hangst, J.S. and Hardy, W.N. and Hayano, R.S. and Hayden, M.E. and Humphries, A.J. and Hydomako, R. and Jonsell, S. and Kemp, S.L. and Kurchaninov, L. and Madsen, N. and Menary, S. and Nolan, P. and Olchanski, K. and Olin, A. and Pusa, P. and Rasmussen, C.O. and Robicheaux, F. and Sarid, E. and Silveira, D.M. and So, C. and Storey, J.W. and Thompson, R.I. and Van Der Werf, D.P. and Wurtele, J.S. and Yamazaki, Y.},
    							title={Confinement of antihydrogen for 1,000 seconds},
    							journal={Nature Physics},
    							year={2011},
    							volume={7},
    							number={7},
    							pages={558-564}
    						}
    					
    J. S. Wurtele, G. Bekefi, R. Chu & K. Xu Prebunching in a collective Raman free-electron laser amplifier 1990 Physics of Fluids B: Plasma Physics
    Vol. 2 (2), pp. 401-406  
    Abstract: Experiments, theory, and simulations are reported on the effects of electron prebunching in a mildly relativistic, low-current (200 kV, 1 A) free-electron laser amplifier operating in the collective (Raman) regime at a frequency of ~10 GHz. Prebunching is established by injecting an electromagnetic wave into a bifilar helical wiggler and then transporting the bunched beam into a second magnetic wiggler region. The wave growth rate, Gamma[equivalent](1/P)(dP/dz), is deduced from measurements of the radiation intensity as a function of interaction length. Observations show that prebunching can increase the radiation growth rate Gamma manyfold as compared with a system without prebunching.
    BibTeX:
    @article{wurtele:401,
      author = {J. S. Wurtele and G. Bekefi and R. Chu and K. Xu},
      title = {Prebunching in a collective Raman free-electron laser amplifier},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1990},
      volume = {2},
      number = {2},
      pages = {401-406},
      url = {http://link.aip.org/link/?PFB/2/401/1},
      doi = {http://dx.doi.org/10.1063/1.859328}
    }
    					
    J. S. Wurtele, R. Chu & J. Fajans Nonlinear theory and experiment of collective free electron lasers 1990 Physics of Fluids B: Plasma Physics
    Vol. 2 (7), pp. 1626-1634  
    Abstract: A theoretical and experimental study of the nonlinear performance of a free electron laser (FEL) amplifier operating in the collective (Raman) regime is reported. The FEL generates up to ~100 kW of rf power at a frequency of 9.3 GHz and an efficiency of ~10%. Power saturation, efficiency, and synchrotron oscillations are studied as a function of rf input power, electron beam energy, current, wiggler field amplitude, and axial distance within the helical wiggler. The influences of the nonlinear electron motion in the ponderomotive potential and space-charge waves are studied by measurements of the dependence of gain and efficiency on the initial radiation intensity. Good agreement with a nonlinear theory that takes cognizance of electron trapping in the combined ponderomotive and space-charge potential well is obtained.
    BibTeX:
    @article{wurtele:1626,
      author = {Jonathan S. Wurtele and Ronson Chu and Joel Fajans},
      title = {Nonlinear theory and experiment of collective free electron lasers},
      journal = {Physics of Fluids B: Plasma Physics},
      publisher = {AIP},
      year = {1990},
      volume = {2},
      number = {7},
      pages = {1626-1634},
      url = {http://link.aip.org/link/?PFB/2/1626/1},
      doi = {http://dx.doi.org/10.1063/1.859488}
    }
    					
    Wurtele, J.S. & A. M. Sessler Constraints on laser-driven accelerators for a high-energy linear collider 1997 Lasers and Electro-Optics, 1997. CLEO '97., Summaries of Papers Presented at the Conference on
    Vol. 11, pp. 313-314  
    Abstract: General consideration of the requirements for a high energy linear collider (here, to be specific, taken to be 1 TeV on 1 TeV) are applied to free-space alser and laser/plasma accelerators. It is shown that the requirements impose very severe constraints upon the new accelerators--so severe, that it seems unlikely that these necessary criteria can be met in the foreseeable future.
    BibTeX:
    @article{603193,
      author = {Wurtele, J.S., and Sessler, A. M.},
      title = {Constraints on laser-driven accelerators for a high-energy linear collider},
      journal = {Lasers and Electro-Optics, 1997. CLEO '97., Summaries of Papers Presented at the Conference on},
      year = {1997},
      volume = {11},
      pages = {313-314}
    }
    					
    O. Yaakobi, L. Friedland, R. R. Lindberg, A. E. Charman, G. Penn & J. S. Wurtele Spatially autoresonant stimulated Raman scattering in nonuniform plasmas 2008 Physics of Plasmas
    Vol. 15 (3), pp. 032105  
    Abstract: New solutions to the coupled three-wave equations in a nonuniform plasma medium are presented that include both space and time dependence of the waves. By including the dominant nonlinear frequency shift of the material wave, it is shown that if the driving waves are sufficiently strong (in relation to the medium gradient), a nonlinearly phase-locked solution develops that is characteristic of autoresonance. In this case, the material (electrostatic) wave develops into a front starting at the linear resonance point and moving with the wave group velocity in a manner such that the intensity increases linearly with the propagation distance. The forms of the other two (electromagnetic) waves follow naturally from the Manley?Rowe relations.
    BibTeX:
    @article{Yaakobi2008,
      author = {O. Yaakobi and L. Friedland and R. R. Lindberg and A. E. Charman and G. Penn and J. S. Wurtele},
      title = {Spatially autoresonant stimulated Raman scattering in nonuniform plasmas},
      journal = {Physics of Plasmas},
      publisher = {AIP},
      year = {2008},
      volume = {15},
      number = {3},
      pages = {032105},
      url = {http://link.aip.org/link/?PHP/15/032105/1},
      doi = {http://dx.doi.org/10.1063/1.2884717}
    }
    					
    N. A. Yampolsky, N. J. Fisch, V. M. Malkin, E. J. Valeo, R. Lindberg, J. S. Wurtele, J. Ren, S. Li, A. Morozov & S. Suckewer Demonstration of detuning and wavebreaking effects on Raman amplification efficiency in plasma 2008 Phys. of Plasma
    Vol. 15 (11), pp. 113104  
    Abstract: A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short laser pulses might, under ideal conditions, convert as much as 90% of the pump energy to the seed pulse. While the theoretical highest possible efficiency of this scheme has not yet been achieved, larger efficiencies than ever before obtained experimentally (6.4%) are now being reported, and these efficiencies are accompanied by strong pulse compression. Based on these recent extensive experiments, it is now possible to deduce that the experimentally realized efficiency of the amplifier is likely constrained by two factors, namely the pump chirp and the plasma wavebreaking, and that these experimental observations may likely involve favorable compensation between the chirp of the laser and the density variation of the mediating plasma. Several methods for further improvement of the amplifier efficiency in current experiments are suggested.
    BibTeX:
    @article{yampolsky:113104,
      author = {N. A. Yampolsky and N. J. Fisch and V. M. Malkin and E. J. Valeo and R. Lindberg and J. S. Wurtele and J. Ren and S. Li and A. Morozov and S. Suckewer},
      title = {Demonstration of detuning and wavebreaking effects on Raman amplification efficiency in plasma},
      journal = {Phys. of Plasma},
      publisher = {AIP},
      year = {2008},
      volume = {15},
      number = {11},
      pages = {113104},
      url = {http://link.aip.org/link/?PHP/15/113104/1},
      doi = {http://dx.doi.org/10.1063/1.3023153}
    }
    					
    E. Yu Backhaus, J. Fajans & J. S. Wurtele Application of Contour Dynamics to Systems with Cylindrical Boundaries 1998 J. Comp. Phys.
    Vol. 145 (1), pp. 462-468  
    BibTeX:
    @article{Yu-Backhaus:1998sw,
      author = {Yu Backhaus, E. and Fajans, J. and Wurtele, J. S.},
      title = {Application of Contour Dynamics to Systems with Cylindrical Boundaries},
      journal = {J. Comp. Phys.},
      year = {1998},
      volume = {145},
      number = {1},
      pages = {462--468},
      url = {http://www.sciencedirect.com/science/article/B6WHY-45J58X0-3J/1/60e1860b68dd5edfbf06c430cd47fcc8}
    }
    					
    X. T. Yu & J. S. Wurtele Calculation of the bunch lengthening threshold [particle accelerator] 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 5, pp. 3327-3329  
    Abstract: A new analysis of the bunch lengthening instability, based on a single synchrotron mode in a distorted potential well, is presented. The nonlinearity of the wakefield plays a critical role. It distorts the equilibrium density from its Gaussian shape, which results in asymmetric corrections to the Sacherer equation. This modified equation will have unstable eigenmodes when the beam current reaches a threshold value. The calculated threshold agrees very well with our multiparticle simulation for SPEAR parameters
    BibTeX:
    @article{Yu1993,
      author = {Yu, X. T. and Wurtele, J. S.},
      title = {Calculation of the bunch lengthening threshold [particle accelerator]},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {5},
      pages = {3327-3329},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309641}
    }
    					
    X. T. Yu, J. S. Wurtele & D. H. Whittum Impedance formalism for an arbitrary cumulative instability 1993 Particle Accelerator Conference, 1993., Proceedings of the 1993
    Vol. 5, pp. 3399-3401  
    Abstract: A formalism is developed for the analysis of collective instabilities in standing-wave systems. The analysis permits a unified treatment of the coupled-cavity free-electron laser, relativistic klystrons and other high power microwave sources. Coupling from both transverse and longitudinal beam motion is included in the calculation of the transverse and longitudinal impedances
    BibTeX:
    @article{309663,
      author = {Yu, X. T. and Wurtele, J. S. and Whittum, D. H.},
      title = {Impedance formalism for an arbitrary cumulative instability},
      journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993},
      year = {1993},
      volume = {5},
      pages = {3399-3401},
      doi = {http://dx.doi.org/10.1109/PAC.1993.309663}
    }