Publications
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, 2226 Jun 1998} } 

A.E. Charman, R.R. Lindberg, J.S. Wurtele & L. Friedland  Robust Autoresonant Excitation in the Plasma BeatWave Accelerator: A Theoretical Study  2005  (TPAE066)  
Abstract: A modified version of the Plasma BeatWave Accelerator scheme is presented, which is based on autoresonant phaselocking 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 BeatWave 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. AlQaradawi, 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. 390395 

Abstract: CERN has a long tradition of pursuing fundamental physics on a variety of energy scales. For antiprotons CERN famously produced the highenergy SPS beam but also the world's only and unique sources of lowenergy antiprotons ? first the Low Energy Antiproton Ring (LEAR) and thereafter the Antiproton Decelerator (AD). The scientific demand for lowenergy antiprotons 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 antiprotons 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 lowenergy antiproton 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 HP 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. AlQaradawi 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 = {390395}, 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 minimumB 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 Penningneutral 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 antiatom trap  2010 
Physics Letters B Vol. 685 (23), pp. 141  145 

Abstract: Antihydrogen production in a neutral atom trap formed by an octupolebased magnetic field minimum is demonstrated using fieldionization of weakly bound antiatoms. Using our unique annihilation imaging detector, we correlate antihydrogen detection by imaging and by fieldionization for the first time. We further establish how fieldionization 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 antiatom.  
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 antiatom trap}, journal = {Physics Letters B}, year = {2010}, volume = {685}, number = {23}, pages = {141  145}, url = {http://www.sciencedirect.com/science/article/B6TVN4Y8PY5V1/2/a4bf62a70fcd93284ec84909a53a2417}, doi = {DOI: 10.1016/j.physletb.2010.01.066} } 

G. B. Andresen, M. D. Ashkezari, M. BaqueroRuiz, 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. 673676 

Abstract: Antimatter was first predicted1 in 1931, by Dirac. Work with highenergy antiparticles is now commonplace, and antielectrons 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 1sto2s transition4), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, modelindependent 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 antiatoms, 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 BaqueroRuiz, 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 = {673676}, url = {http://dx.doi.org/10.1038/nature09610}, doi = {http://dx.doi.org/10.1038/nature09610} } 

G. B. Andresen, M. D. Ashkezari, M. BaqueroRuiz, 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 longstanding goal.  
BibTeX:
@article{PhysRevLett.105.013003, author = {Andresen, G. B. and Ashkezari, M. D. and BaqueroRuiz, 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 antiatom 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{09534075411011001, 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 antiatom 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/09534075/41/011001} } 

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. 241248 

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 minimumB 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 = {241248}, 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. 96105 

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 nearaxis 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 = {96105}, 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 PenningMalmberg 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 nearaxis 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 zerorotation frequency bounceresonant loss in a PenningMalmberg trap used for antihydrogen trapping  2009 
Physics of Plasmas Vol. 16 (10), pp. 100702 

Abstract: In many antihydrogen trapping schemes, antiprotons held in a shortwell Penning?Malmberg trap are released into a longer well. This process necessarily causes the bounceaveraged 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 bounceresonant 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 zerorotation frequency bounceresonant loss in a PenningMalmberg 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 34 and 0.5 TeV centerofmass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory for the schannel 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 heavyZ 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 HighEnergy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].  
BibTeX:
@article{ankenbrandt19992, 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. BenZvi, P. Catravas, J.M. Fang, T. C. Marshall, X. J. Wang, J. S. Wurtele, V. Yakimenko & L. H. Yu  First observation of selfamplified 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 (13), pp. 267270 

Abstract: We report evidence of selfamplified spontaneous emission at 1064†nm. Single pass, onaxis 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 01†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 BenZvi, I. and Catravas, P. and Fang, JM. and Marshall, T. C. and Wang, X. J. and Wurtele, J. S. and Yakimenko, V. and Yu, L. H.}, title = {First observation of selfamplified 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 = {13}, pages = {267270}, url = {http://www.sciencedirect.com/science/article/B6TJM3VHNRSY1X/1/567cbfd88482f8a38e078ef479d370b3} } 

M. Babzien, I. BenZvi, P. Catravas, J.M. Fang, T. C. Marshall, X. J. Wang, J. S. Wurtele, V. Yakimenko & L. H. Yu  Observation of selfamplified spontaneous emission in the nearinfrared and visible wavelengths  1998 
Phys. Rev. E Vol. 57 (5), pp. 60936100 

Abstract: We report evidence of selfamplified 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. Singlepass, onaxis 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 01 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 BenZvi, 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 selfamplified spontaneous emission in the nearinfrared and visible wavelengths}, journal = {Phys. Rev. E}, publisher = {American Physical Society}, year = {1998}, volume = {57}, number = {5}, pages = {60936100}, doi = {http://dx.doi.org/10.1103/PhysRevE.57.6093} } 

E. Y. Backhaus  Collisionless Relaxation in BeamPlasma Systems  2001  School: University of California at Berkeley  
BibTeX:
@phdthesis{Backhaus, author = {Backhaus, E. Yu.}, title = {Collisionless Relaxation in BeamPlasma Systems}, school = {University of California at Berkeley}, year = {2001} } 

E. Y. Backhaus & J. S. Wurtele  Coupled moment expansion model for the dynamics in a beamplasma system  2000 
Phys. of Plasma Vol. 7 (11), pp. 47294747 

Abstract: A new technique is developed to study beam dynamics in an overdense plasma. This technique is an alternative to, and extension of, the wellknown 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 particleincell simulations for a wide range of system parameters. New analytical results for the secondorder moments in the phasemixed state are obtained. Unlike previous results, these connect the final values of the secondorder moments with the initial beam mismatch. These analytical estimates are in good agreement with the CME model and particleincell simulations.  
BibTeX:
@article{backhaus:4729, author = {E. Yu. Backhaus and J. S. Wurtele}, title = {Coupled moment expansion model for the dynamics in a beamplasma system}, journal = {Phys. of Plasma}, publisher = {AIP}, year = {2000}, volume = {7}, number = {11}, pages = {47294747}, 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  Plasmalens experiments at the Final Focus Test Beam  1993 
Particle Accelerator Conference, 1993., Proceedings of the 1993 Vol. 4, pp. 26382640 

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 beaman effect which has never been observed beforeshould 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 = {Plasmalens experiments at the Final Focus Test Beam}, journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993}, year = {1993}, volume = {4}, pages = {26382640}, 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. 606611 

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 gasthe 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 = {606611}, 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 (12), pp. 134  138 

Abstract: Hydrodynamic simulations have been carried out using the multiphysics radiation hydrodynamics code HYDRA and the simplified onedimensional hydrodynamics code DISH. We simulate possible targets for a nearterm experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCXII) for studies of warm dense matter and inertial fusion energyrelated beamtarget coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include singlepulse planar metallic solid and foam foils. Concepts for doublepulsed and rampedenergy pulses on cryogenic targets and foams have been simulated for exploring direct drive beamtarget 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 = {12}, 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/B6TJM4W0R0GP8/2/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 (12), 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 multiphysics 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 socalled 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 twophase (fluidvapor) 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 = {12}, pages = {275  283}, note = {Proceedings of the 16th International Symposium on Heavy Ion Inertial Fusion  HIF 06}, url = {http://www.sciencedirect.com/science/article/B6TJM4N3WYF8C/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. 25682570  
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 phasespace 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 = {25682570} } 

G. Bekefi, J. S. Wurtele & I. H. Deutsch  Freeelectronlaser radiation induced by a periodic dielectric medium  1986 
Phys. Rev. A Vol. 34 (2), pp. 12281236 

Abstract: Stimulated emission by an unaccelerated electron beam propagating through a periodically modulated dielectric is studied. The laser gain in the lowgain regime is calculated for the case of a cold, tenuous electron beam by applying the Einsteincoefficient technique in the classical limit ħ→0. In the highgain, strongpump regime equations for the evolution of the electron beam dynamics and of the radiation are developed using a selfconsistent, onedimensional model for the interaction. Analytic calculations of the smallsignal 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 = {Freeelectronlaser radiation induced by a periodic dielectric medium}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {1986}, volume = {34}, number = {2}, pages = {12281236}, 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 FELbased 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 FELbased 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 selfconsistent collective neutrinoplasma interactions  2000 
Phys. Rev. E Vol. 61 (4), pp. 44104421 

Abstract: A Lagrangian formalism for selfconsistent collective neutrinoplasma interactions is presented in which each neutrino species is described as a classical ideal fluid. The neutrinoplasma fluid equations are derived from a covariant relativistic variational principle in which finitetemperature 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 neutrinoplasma interactions.  
BibTeX:
@article{PhysRevE.61.4410, author = {Brizard, A. J. and Murayama, H. and Wurtele, J. S.}, title = {Magnetic field generation from selfconsistent collective neutrinoplasma interactions}, journal = {Phys. Rev. E}, publisher = {American Physical Society}, year = {2000}, volume = {61}, number = {4}, pages = {44104421}, doi = {http://dx.doi.org/10.1103/PhysRevE.61.4410} } 

A. J. Brizard & J. S. Wurtele  Lagrangian formulation for neutrinoplasma interactions  1999 
Phys. of Plasma Vol. 6 (4), pp. 13231328 

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 selfconsistent (collective) treatment of neutrinoplasma interactions, quantum effects are ignored throughout and the (spinless) neutrinos are represented by a complexvalued KleinGordon 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 electromagneticplasma 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 neutrinoplasma interactions}, journal = {Phys. of Plasma}, publisher = {AIP}, year = {1999}, volume = {6}, number = {4}, pages = {13231328}, 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 laserlasma 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 counterpropagating 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, 2226 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, 2226 Jun 1998} } 

P. Catravas, W. P. Leemans, J. S. Wurtele, M. S. Zolotorev, M. Babzien, I. BenZvi, Z. Segalov, X.J. Wang & V. Yakimenko  Measurement of ElectronBeam Bunch Length and Emittance Using ShotNoiseDriven Fluctuations in Incoherent Radiation  1999 
Phys. Rev. Lett. Vol. 82 (26), pp. 52615264 

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 15 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 BenZvi, I. and Segalov, Z. and Wang, X.J. and Yakimenko, V.}, title = {Measurement of ElectronBeam Bunch Length and Emittance Using ShotNoiseDriven Fluctuations in Incoherent Radiation}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1999}, volume = {82}, number = {26}, pages = {52615264}, 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 highprecision 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 highprecision 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 highresolution laser spectroscopy on the 1S2S 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 1S2S spectroscopy of trapped atoms in a regime not discussed before. Nous avons produit de l?antihydrog�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?antihydrog�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 1S2S 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 1S2S 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=ehostlive} } 

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. 22812291 

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 firstorder perturbation theory where it is shown, under the assumption of no degeneracy, that there are only stable oscillations. Secondorder 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 = {22812291}, 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. 359361 

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 = {359361}, 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 LaserPlasma Interactions  2007  School: University of California at Berkeley  
BibTeX:
@phdthesis{Charman, author = {Charman, A. E.}, title = {Random Aspects of Beam Physics and LaserPlasma Interactions}, school = {University of California at Berkeley}, year = {2007} } 

A. E. Charman, G. Penn & J. S. Wurtele M. Conde & C. Eyberger (Hrsg.)  A HilbertSpace Variational Principle for Spontaneous Wiggler and Synchrotron Radiation  2006 
Advanced Accelerator Concepts: 12th Advanced Accelerator Concepts Workshop Vol. 877 (1), pp. 381387 

Abstract: Within the framework of Hilbert space theory, we have developed a maximumpower variational principle applicable to classical spontaneous radiation from prescribed classical harmonic current sources. A simple proof is summarized for the case of threedimensional 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 HilbertSpace 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 = {381387}, 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 TransitTime Optical Stochastic Cooling of Muons  2009  
Abstract: Ultrafast 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 highbandwidth amplifiers so as to limit the incoherent heating effects from neighboring particles. A method of transittime optical stochastic cooling has been proposed which would employ highgain, highbandwidth, solidstate lasers to amplify the spontaneous radiation from the charged particle bunch in a strongfield 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{charman2009, author = {A. E. Charman and J. S. Wurtele}, title = {Quantum Mechanical Treatment of TransitTime 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 Hilbertspace formulation of and variational principle for spontaneous wiggler radiation  2005  
Abstract: Within the framework of Hilbert space theory, we derive a maximumpower variational principle applicable to classical spontaneous radiation from prescribed harmonic current sources. Results are first derived in the paraxial limit, then appropriately generalized to nonparaxial situations. The techniques were developed within the context of undulator radiation from relativistic electron beams, but are more broadly applicable.  
BibTeX:
@misc{charman2005, author = {A. E. Charman and J. S. Wurtele}, title = {A Hilbertspace 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 Highenergy 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 spacecharge waves of a helical relativistic electron beam on the cyclotron maser instability  1992 
Plasma Science, IEEE Transactions on Vol. 20 (3), pp. 149154 

Abstract: The influence of the longitudinal spacecharge waves of a coherently gyrophased helical relativistic electron beam on the cyclotron maser instability is investigated in a cylindrical waveguide configuration using a threedimensional 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 spacecharge waves on a coherently gyrophased beam are suppressed in a waveguide geometry, in comparison with an ideal onedimensional 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 spacecharge 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 = {149154}, doi = {http://dx.doi.org/10.1109/27.142814} } 

C. Chen, J. A. Davies, G. Zhang & J. S. Wurtele  Largeamplitude traveling electromagnetic waves in collisionless magnetoplasmas  1992 
Phys. Rev. Lett. Vol. 69 (1), pp. 7376 

Abstract: A class of exact largeamplitude travelingwave solutions to the nonlinear VlasovMaxwell equations describing a onedimensional collisionless magnetized plasma is obtained. These waves are complementary to the electrostatic BernsteinGreeneKruskal 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 trappedparticle distribution function.  
BibTeX:
@article{PhysRevLett.69.73, author = {Chen, C. and Davies, J. A. and Zhang, G. and Wurtele, J. S.}, title = {Largeamplitude traveling electromagnetic waves in collisionless magnetoplasmas}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1992}, volume = {69}, number = {1}, pages = {7376}, 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. 21332148 

Abstract: The interaction of multiple waveguide modes with a relativistic electron beam in an overmoded, singlefrequency, cyclotron autoresonance maser amplifier is analyzed using a nonlinear selfconsistent 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 radiofrequency (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 = {21332148}, 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. 33893392 

Abstract: The interaction of transverse eigenmodes with a relativistic electron beam is analyzed in an overmoded cyclotron autoresonance maser amplifier, using a nonlinear selfconsistent 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 = {33893392}, 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. 489492 

Abstract: The efficiency of cyclotron autoresonance maser (CARM) amplifiers with piecewise linear tapering of the magnetic field is analyzed. In the lowcurrent 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 highcurrent, highgain, 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 = {489492}, 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. 893895 

Abstract: We report experimental high power test results on a high gradient 17 GHz RF photocathode gun. The 1½ cell, πmode, copper cavity was tested with 510 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 onaxis 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 = {893895}, 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. 25752577 

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 mmmrad, 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 = {25752577}, 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. 422424 

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 impedancerelated instabilities are given for two cases of current interesta 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 nonlinear longitudinal chromaticity)  
BibTeX:
@article{749676, author = {WenHao 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 = {422424}, doi = {http://dx.doi.org/10.1109/PAC.1997.749676} } 

W.H. Cheng, A. M. Sessler & J. S. Wurtele  Increase of the transverse strong headtail stability threshold by an alternating chromaticity  1997 
Particle Accelerator Conference, 1997. Proceedings of the 1997 Vol. 2, pp. 16141616 

Abstract: It has been shown that the transverse headtail instability can be suppressed by modulating the chromaticity over a synchrotron period. In this work, we demonstrate that the threshold of the strong headtail instability can be significantly increased by the alternating chromaticity (AC). We present results of multiparticle simulation and a new criterion for the SHT instability  
BibTeX:
@article{750776, author = {WenHao Cheng and Sessler, A. M. and Wurtele, J. S.}, title = {Increase of the transverse strong headtail stability threshold by an alternating chromaticity}, journal = {Particle Accelerator Conference, 1997. Proceedings of the 1997}, year = {1997}, volume = {2}, pages = {16141616}, 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 headtail instability  1997 
Phys. Rev. E Vol. 56 (4), pp. 46954709 

Abstract: A detailed analytical and numerical study of the suppression of the transverse headtail 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 headtail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physical mechanisms of the damping scheme are rotation of the headtail 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, WenHao and Sessler, Andrew M. and Wurtele, Jonathan S.}, title = {Varying chromaticity: A damping mechanism for the transverse headtail instability}, journal = {Phys. Rev. E}, publisher = {American Physical Society}, year = {1997}, volume = {56}, number = {4}, pages = {46954709}, doi = {http://dx.doi.org/10.1103/PhysRevE.56.4695} } 

W.H. Cheng, A. M. Sessler & J. S. Wurtele  Damping of the Transverse HeadTail Instability by Periodic Modulation of the Chromaticity  1997 
Phys. Rev. Lett. Vol. 78 (24), pp. 45654568 

Abstract: An analytical and numerical study of the suppression of the transverse headtail 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 headtail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physical mechanisms of the damping scheme are rotation of the headtail 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, WenHao and Sessler, Andrew M. and Wurtele, Jonathan S.}, title = {Damping of the Transverse HeadTail Instability by Periodic Modulation of the Chromaticity}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1997}, volume = {78}, number = {24}, pages = {45654568}, 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 wakefield acceleration and optical guiding in a hollow plasma channel  1995 
Phys. of Plasma Vol. 2 (1), pp. 310318 

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 twodimensional (2D) particleincell (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 onehalf 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 wakefield acceleration and optical guiding in a hollow plasma channel}, journal = {Phys. of Plasma}, publisher = {AIP}, year = {1995}, volume = {2}, number = {1}, pages = {310318}, 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. 23782386 

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 vortexincell 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 = {23782386}, 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 VUVsoft Xray 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 VUVsoft Xray 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 freeelectron lasers  1987 
Quantum Electronics, IEEE Journal of Vol. 23 (1), pp. 103116 

Abstract: The operation of freeelectron lasers (FEL's) with axial electron beams and highpower electromagnetic wiggler fields such as those produced by highpower 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 highgain 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 electromagnetic 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 freeelectron lasers}, journal = {Quantum Electronics, IEEE Journal of}, year = {1987}, volume = {23}, number = {1}, pages = {103116} } 

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. 223225 

Abstract: The CARM (cyclotron autoresonance maser) is a promising source of microwave power for the next generation of linear collider. Designs for a highpower 17.136GHz CARM amplifier, utilizing a 700kV pulse modulator and a 1.2MeV linear induction accelerator, are presented. These designs are attractive for a proofofprinciple CARM amplifier experiment. Interaction efficiencies are in the 3050% 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 = {223225}, 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. 28252838 

Abstract: The detailed influence of an untrappedelectron population on the sideband instability in a helical wiggler free electron laser is investigated for smallamplitude perturbations about a constantamplitude (ahat ^{0}_{s} =const) primary electromagnetic wave with slowly varying equilibrium phase delta^{0}_{s}. 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 singleparticle 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 =nhat u /nhat 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 untrappedelectron 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 untrappedelectron mode increases until only the untrappedelectron 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 untrappedelectron 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 = {28252838}, 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  Singleparticle analysis of the freeelectron laser sideband instability for primary electromagnetic wave with constant phase and slowly varying phase  1987 
Physics of Fluids Vol. 30 (2), pp. 557569 

Abstract: Use is made of the singleparticle orbit equations together with Maxwell's equations and appropriate statistical averages to investigate detailed properties of the sideband instability for a helicalwiggler freeelectron laser with wiggler wavelength lambda0=2pi/k0=const and normalized wiggler amplitude aw=eBhat w/mc2k0 =const. The model describes the nonlinear evolution of a rightcircularly polarized primary electromagnetic wave with frequency omegas, wavenumber ks, and slowly varying amplitude ahat 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 smallamplitude perturbations about a quasisteady equilibrium state characterized by ahat ^{0}_{s} =const (independent of z[script '] and t[script ']). Two cases are treated. The first case assumes constant equilibrium wave phase delta^{0}_{s} =const, which requires (for selfconsistency) both untrapped and trappedelectron populations satisfying <[summation]j exp[ik^{[script ']}_{p}z^{}_{j0}(t[script ']) +idelta^{0}_{s}]/gamma^{[script ']}_{j}>=0.Here k^{}_{p}=(ks+k0)/gammap is the wavenumber of the ponderomotive potential, z^{[script ']}_{j0}(t[script ']) is the equilibrium orbit, and gamma^{}_{j}mc2 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, [partialderivative]delta^{0}_{s}/[partialderivative]z[script ']=2Gamma0(Gamma0ck0/OmegaB)2 k^{[script ']}_{p}[notequal]0. The resulting dispersion relations and detailed stability properties are found to be quite different in the two cases. Both the weakpump and strongpump regimes are considered.  
BibTeX:
@article{davidson:557, author = {Ronald C. Davidson and Jonathan S. Wurtele}, title = {Singleparticle analysis of the freeelectron 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 = {557569}, 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 freeelectron laser for electrons trapped near the bottom of the ponderomotive potential  1986 
Phys. Rev. A Vol. 34 (4), pp. 30633076 

Abstract: A kinetic formalism based on the VlasovMaxwell equations is used to investigate properties of the sideband instability for a tenuous, relativistic electron beam propagating through a constantamplitude 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 BernsteinGreeneKruskal state in which the distribution of beam electrons Gs(γ') and the wiggler magnetic field coexist in quasisteady equilibrium with a finiteamplitude, 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=(1vp2/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 freeelectron 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 = {30633076}, 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. 17551765 

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 68 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 threedimensional simulation code that has been developed to investigate the selfconsistent 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 = {17551765}, 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. 30813084 

Abstract: Nonparaxial propagation of ultrashort, highpower laser pulses in plasma channels is examined. In the adiabatic limit, pulse energy conservation, nonlinear group velocity, damped betatron oscillations, selfsteepening, selfphase modulation, and shock formation are analyzed. In the nonadiabatic limit, the coupling of forward Raman scattering (FRS) and the selfmodulation 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 = {30813084}, 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. 214222 

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, selfsteepening, selfphase modulation, and shock formation are analyzed. In the nonadiabatic limit, the coupling of forward Raman scattering (FRS) and the selfmodulation 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 = {214222}, 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 threedimensional free electron laser simulation  1997 
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 393 (13), pp. 277279 

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 steadystate (timeindependent) amplifier code. The code selfconsistently 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 (noncorrelated phasespace 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 threedimensional 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 = {13}, pages = {277279}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPTFJX79/1/758b57e271e9603fec436dad6a3993a7} } 

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 higherorder multipoles used in antihydrogen traps  2006 
NonNeutral Plasma Physics VI: Workshop on NonNeutral Plasmas 2006 Vol. 862 (1), pp. 176180 

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 higherorder multipoles used in antihydrogen traps}, journal = {NonNeutral Plasma Physics VI: Workshop on NonNeutral Plasmas 2006}, publisher = {AIP}, year = {2006}, volume = {862}, number = {1}, pages = {176180}, 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 freeelectron laser nonlinear ponderomotive trapping buckets  1991 
Quantum Electronics, IEEE Journal of Vol. 27 (12), pp. 25462549 

Abstract: Experimental and computational studies of freeelectron lasers (FELs) operating at high input powers have been undertaken. These studies constitute a novel method of investigating saturation and trapping effects in freeelectron 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 freeelectron laser nonlinear ponderomotive trapping buckets}, journal = {Quantum Electronics, IEEE Journal of}, year = {1991}, volume = {27}, number = {12}, pages = {25462549}, 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 freeelectron lasers  1989 
Physics of Fluids B: Plasma Physics Vol. 1 (10), pp. 20732084 

Abstract: The freeelectron laser (FEL)induced modifications to the vacuum waveguide modes are calculated for lowfrequency 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 spacecharge wave.  
BibTeX:
@article{fajans:2073, author = {J. Fajans and J. S. Wurtele}, title = {Waveguide mode deformation in freeelectron lasers}, journal = {Physics of Fluids B: Plasma Physics}, publisher = {AIP}, year = {1989}, volume = {1}, number = {10}, pages = {20732084}, 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 freeelectron lasers  1988 
Quantum Electronics, IEEE Journal of Vol. 24 (9), pp. 1800518006 

Abstract: The suppression of feedback oscillations in a freeelectron 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 5mmwavelength FEL with a 40dB attenuator inserted in the interaction region  
BibTeX:
@article{7116, author = {Fajans, J. and Wurtele, J. S.}, title = {Suppression of feedback oscillations in freeelectron lasers}, journal = {Quantum Electronics, IEEE Journal of}, year = {1988}, volume = {24}, number = {9}, pages = {1800518006}, 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 FreeElectron Laser Amplifier  1986 
Phys. Rev. Lett. Vol. 57 (5), pp. 579582 

Abstract: We report measurements of the nonlinear radiation intensity and phase (wave refractive index) of a freeelectron 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 spacecharge 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 FreeElectron Laser Amplifier}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1986}, volume = {57}, number = {5}, pages = {579582}, 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. 43054317 

Abstract: The excitation of synchronized Bernstein, Greene, and Kruskal (BGK) modes in a pure electron plasma confined in MalmbergPenning trap is studied. The modes are excited by controlling the frequency of an oscillating external potential. Initially, the drive resonates with, and phaselocks to, a group of axially bouncing electrons in the trap. These initially phaselocked electrons remain phaselocked (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 = {43054317}, 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. 339343  
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 welldefined 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 highenergy 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 DriftTube Linac, RF, singlegap, IonizationFront Accelerator, and PulseLine 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 = {339343} } 

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. 8189 

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 = {8189}, url = {http://dx.doi.org/10.1007/s1075100795272} } 

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. 208220 

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 = {208220}, 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 byproduct 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 wedgeshaped 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 nonzero 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 Xray 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 lowgain 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 LowGain 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 lowgain regime based on trial functions for the output radiation. Full threedimensional 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 Xray 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 LowGain 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 CourantSnyder 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, 2125 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 threedimensional particleincell (3D 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 MalmbergPenning 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 MalmbergPenning 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 3D 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 nonneutral 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, nonneutral plasma confined in a PenningMalmberg 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 twodimensional particleincell (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 nonneutral 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 nonneutral 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 threedimensional computational equilibrium of nonneutral 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 nonneutral plasmas require the numerical realization of a threedimensional plasma distribution. This paper presents a new numerical method for obtaining, without an explicit model for physical collisions in the code, a low noise threedimensional 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 antihydrogen experiment, using the threedimensional particleincell 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 nonneutral 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 threedimensional computational equilibrium of nonneutral plasmas using WARP}, journal = {Journal of Computational Physics}, year = {2007}, volume = {225}, number = {2}, pages = {1736  1752}, url = {http://www.sciencedirect.com/science/article/B6WHY4N85BD51/2/bc0ba259790de0678b9acb2378cb8840}, doi = {DOI: 10.1016/j.jcp.2007.02.029} } 

V. V. Gorgadze, L. Friedland & J. S. Wurtele  Autoresonant control of a preexcited diocotron mode  2007 
Phys. of Plasma Vol. 14 (8), pp. 082317 

Abstract: A new method for the manipulation of a preexcited l = 1 diocotron mode in a pure electron plasma in a MalmbergPenning 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 selfphaselocked 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 preexcited 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  Spacecharge 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 selffield dynamics near the cathode. The particleincell 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 flattop and Gaussian bunch profiles.  
BibTeX:
@conference{Gorgadze:TPPE064, author = {V. V. Gorgadze and J. S. Wurtele}, title = {Spacecharge 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. 32023205 

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 13 cm long plasma with density around 1014 cm3. 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 particleincell 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 = {32023205}, doi = {http://dx.doi.org/10.1103/PhysRevLett.83.3202} } 

M. E. Griswold, N. J. Fisch & J. S. Wurtele  An upper bound to timeaveraged spacecharge limited diode currents  2010 
Physics of Plasmas Vol. 17 (11), pp. 114503 

Abstract: The Child?Langmuir law limits the steadystate current density across a onedimensional 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 timedependent conditions. For the case where the applied voltage is constant but the electric field at the cathode is allowed to vary in time, onedimensional particleincell simulations suggest that such a violation is impossible. Although a formal proof is not given, an upper bound on the timeaveraged current density is offered.  
BibTeX:
@article{Griswold2010, author = {M. E. Griswold and N. J. Fisch and J. S. Wurtele}, title = {An upper bound to timeaveraged spacecharge 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 `zerothorder' design.  
BibTeX:
@misc{group1996, 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:hepex/9605011} } 

M. Gullans, G. Penn, J. S. Wurtele & M. Zolotorev  Threedimensional analysis of freeelectron laser performance using brightness scaled variables  2008 
Phys. Rev. ST Accel. Beams Vol. 11 (6), pp. 060701 

Abstract: A threedimensional analysis of radiation generation in a freeelectron 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 sixdimensional beam brightness. The sixdimensional 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 onedimensional growth rate. The brightnessscaled 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 = {Threedimensional analysis of freeelectron 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 Xray harmonic generation FEL seeded with an EUV laser pulse  2007 
Optics Communications Vol. 274 (1), pp. 167175 

Abstract: The performance of a free electron laser (FEL) using a lowpower extreme ultraviolet (EUV) pulse as an input seed is investigated. The parameters are appropriate for 30†nm seeds produced from highpower Ti:Sapphire pulses using high harmonic generation schemes. It is found that, for reasonable beam parameters, robust FEL performance can be obtained. Both timeindependent and timedependent simulations are performed for varying system parameters using the GENESIS simulation code. A comparison is made with a twostage harmonic FEL that is seeded by a highpower 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 Xray harmonic generation FEL seeded with an EUV laser pulse}, journal = {Optics Communications}, year = {2007}, volume = {274}, number = {1}, pages = {167175}, url = {http://www.sciencedirect.com/science/article/B6TVF4N56NS44/1/831b8447a699de1eda6a9c916f5ad0aa} } 

F. Hartemann, K. Xu, G. Bekefi, J. S. Wurtele & J. Fajans  Wave profile modification (optical guiding) induced by freeelectron laser interaction  1987 
Phys. Rev. Lett. Vol. 59 (11), pp. 11771180 

Abstract: Modification of the transverse intensity profile of a single electromagnetic waveguide mode during the freeelectron laser (FEL) interaction has been measured. This effect is the waveguide analog to freespace optical guiding. The studies were carried out at microwave frequencies (812 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 FELinduced 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 freeelectron laser interaction}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1987}, volume = {59}, number = {11}, pages = {11771180}, 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. 684686 

Abstract: This paper explores the use of the large electric fields of highbrightness 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≫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 = {684686}, 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. 52045211 

Abstract: A numerical code based on an eikonal formalism has been developed to simulate laserplasma 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 timeaveraged 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 threewave 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 selfconsistent plasma electric field. The code agrees well, in the appropriate regimes, with the results from threewave equations and particleincell 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 threewave 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 = {52045211}, 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  Twodimensional 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 twodimensional, axisymmetric kinetic model. The twodimensional averaged particleincell (aPIC) simulation assumes slowly varying field envelopes and is comprised of onedimensional submodels 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 = {Twodimensional 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/B6TJ54VF56Y02/2/3c1134f0d2bbb1e9ae70edd37858b815}, 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 plasmabased 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 twodimension particleincell 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 particleincell 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/B6TVM4RDR18N4/2/7f3b590ba47930e51cd8b5aefee5ee61}, 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. 30043011 

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 righthand 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 onedimensional particleincell 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 particleincell 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 = {30043011}, 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. 802809 

Abstract: Recently it was found [13] that a magnetized plasma can be made transparent to a righthand 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 = {802809}, 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 (13), pp. 489492 

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 = {13}, pages = {489492}, url = {http://www.sciencedirect.com/science/article/B6TJM497C66C4S/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 vuvsoft xray 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 xray 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 xray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhancedSASE (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 electronlattice energy transfer times in crystalline solids. ∑ ~100 femtoseconds, characteristic of atomic vibrational periods in molecules and solids. ∑ ~10 femtoseconds, characteristic of electronelectron scattering times in solids. ∑ ~100 attoseconds, characteristic of electronelectron correlations and valence electron motion. The needs to directly probe electronic structure and dynamics demand a focus on the VUV and soft xray regions, and the creation of experimental facilities that complement those being constructed with hard xray 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 vuvsoft xray 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 Xray Science  2004  (THPOS51)  
Abstract: LUX is a design study to develop concepts for future ultrafast xray facilities. Presently, LUX is based on an electron beam accelerated to 3GeV energy in a superconducting, recirculating linac. Included in the design are multiple freeelectron laser (FEL) beamlines which use the harmonic cascade approach to produce coherent XUV & soft Xray emission beginning with a strong input seed at 200nm wavelength obtained from a "conventional" laser. Each cascade module generally operates in the lowgain 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 Xray 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 Linacbased Facility for Ultrafast Xray 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 Linacbased Facility for Ultrafast Xray 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 MITBates South Hall Ring  1991 
Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE Vol. 3, pp. 17911793 

Abstract: Instability growth rates and thresholds have been calculated for the MITBates 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 MITBates South Hall Ring}, journal = {Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE}, year = {1991}, volume = {3}, pages = {17911793}, 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 startup phase of a freeelectron laser oscillator  1991 
Quantum Electronics, IEEE Journal of Vol. 27 (12), pp. 25122521 

Abstract: Experimental observations and a theoretical analysis of periodic radiation bursts and macropulse formation in the startup phase of a freeelectron 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 bellshaped macropulses, each of which is composed of a periodic sequence of short micropulses. The micropulses are separated by a cavity roundtrip time. Each bellshaped 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 startup phase of a freeelectron laser oscillator}, journal = {Quantum Electronics, IEEE Journal of}, year = {1991}, volume = {27}, number = {12}, pages = {25122521}, doi = {http://dx.doi.org/10.1109/3.104127} } 

E. Jerby, G. Bekefi & J. S. Wurtele  Observations of periodic intensity bursts during the startup phase of a freeelectronlaser oscillator  1991 
Phys. Rev. Lett. Vol. 66 (16), pp. 20682071 

Abstract: Observations of periodic intensity bursts during the startup phase of a freeelectronlaser oscillator operating in the microwave regime are reported. The bursts are composed of radiation micropulses several nanoseconds wide and separated by the resonantcavity roundtrip time (∼35 ns). The occurrence of the bursts is correlated to random current spikes superposed on the continuous electronbeam current density. The observations are compared with theoretical results from an impulse response model of a freeelectron laser.  
BibTeX:
@article{PhysRevLett.66.2068, author = {Jerby, E. and Bekefi, G. and Wurtele, J. S.}, title = {Observations of periodic intensity bursts during the startup phase of a freeelectronlaser oscillator}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1991}, volume = {66}, number = {16}, pages = {20682071}, 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/B6TJN4RC2RVC8/2/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. 773775 

Abstract: Progress on modeling plasmabased 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 nonideal 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 = {773775}, 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 laserplasma accelerators  1993 
Particle Accelerator Conference, 1993., Proceedings of the 1993 Vol. 4, pp. 26352637 

Abstract: Theory and simulation of shortpulse laser plasma accelerators is presented. The plasma beat wave and laser wakefield accelerators are examined for the parameters of recently developed highbrightness 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 multiGeV acceleration of beams with high beam quality are examined, including optical guiding of the lasers, nonlinear laser and wake velocity shifts, and longterm 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 laserplasma accelerators}, journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993}, year = {1993}, volume = {4}, pages = {26352637}, doi = {http://dx.doi.org/10.1109/PAC.1993.309411} } 

Y. Kawai, H. Saito & J. S. Wurtele  Competing instabilities in the circular freeelectron laser  1991 
Physics of Fluids B: Plasma Physics Vol. 3 (6), pp. 14851495 

Abstract: A small signal theory of the circular freeelectron 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 freeelectron laser}, journal = {Physics of Fluids B: Plasma Physics}, publisher = {AIP}, year = {1991}, volume = {3}, number = {6}, pages = {14851495}, 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. 30563058 

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 broadband impedance. In addition to the BNS damping, tune spreads due to chromaticity, amplitude dependent tune shift and the beambeam interaction are taken into account. It is shown that each of these tune spreads adequately stabilize the transverse dynamics  
BibTeX:
@article{792144, author = {EunSan 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 = {30563058}, 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≃106, 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=3×105) 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, EunSan 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. 30533055 

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≃106, 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 headtotail 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=3×105) 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 = {FunSan 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 = {30533055}, 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 (UCRLCONF216926), 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 W7405Eng48.  
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 = {UCRLCONF216926}, 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. 21352137 

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 = {21352137}, 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. 4041 

Abstract: Raman amplification of a short laser pulse by a counterpropagating pump in a plasma is simulated with a onedimensional electromagnetic particleincell 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 = {4041}, 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. 136145 

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 selfmodulated laser wakefield regime by tightly focusing (spot diameter 8 µm) a single high power (<=10 TW), ultrashort (>=50 fs) laser pulse onto a high density (>1019 cm3) 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 mmmrad), 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 = {136145}, 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  Laserdriven plasmabased 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. 16151623 

Abstract: Plasmabased accelerators are discussed in which highpower 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 timesynchronized ultrashort electron bunches. From scaling laws laser requirements are obtained for development of compact highenergy accelerators. Simulation results of laser guiding and wakefield excitation in plasma channels, as well as laserbased injection of particles into a plasma wake, are presented. Details of the experimental program at Lawrence Berkeley National Laboratory on laser guiding, laser wakefieldbased 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 = {Laserdriven plasmabased 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 = {16151623}, 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. 20262028 

Abstract: The performance of a highfrequency (17GHz), high accelerating gradient (250 MV/m) photocathode RF gun is studied with the particleincell code MAGIC. For the parameter regime of interest, i.e., bunch charge smaller than 1 nC and bunch length shorter than 2 ps, spacecharge forces and finitebunchlength 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 highquality 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 = {20262028}, 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 sidewall coupling in RF guns  1993 
Particle Accelerator Conference, 1993., Proceedings of the 1993 Vol. 4, pp. 26992701 

Abstract: Waveguide sidewall coupling for RF guns is investigated both theoretically and experimentally. We model this aperturecoupling 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 πmode and 0mode, we show that only the πmode 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 sidewall coupling in RF guns}, journal = {Particle Accelerator Conference, 1993., Proceedings of the 1993}, year = {1993}, volume = {4}, pages = {26992701}, 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 broadwall coupled RF gun structures  1997 
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 384 (23), pp. 274284 

Abstract: An equivalent network for a waveguide broadwall 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 broadwall 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 broadwall 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 = {23}, pages = {274284}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPCMY91K/1/b194984564fb48da7d2176b21863b28b} } 

L. C. L. Lin, S. C. Chen & J. S. Wurtele  Waveguide broadwall coupling for RF guns  1995 
Particle Accelerator Conference, 1995., Proceedings of the 1995 Vol. 2, pp. 954956 

Abstract: A theoretical analysis of the waveguide broadwall 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 1½cell RF gun  
BibTeX:
@article{505093, author = {Lin, L. C. L. and Chen, S. C. and Wurtele, J. S.}, title = {Waveguide broadwall coupling for RF guns}, journal = {Particle Accelerator Conference, 1995., Proceedings of the 1995}, year = {1995}, volume = {2}, pages = {954956}, 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. 951953 

Abstract: A frequency scaling law for RF guns is derived from the normalized VlasovMaxwell 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 = {951953}, doi = {http://dx.doi.org/10.1109/PAC.1995.505092} } 

R. Lindberg, A. Charman & J. Wurtele  Reduced kinetic description of weaklydriven 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 selfconsistent electrostatic evolution. This model is based on the adiabatic motion of electrons in the wave to describe Bernstein?Greene?Kruskallike 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 phasemixed, 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 threewavetype 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 weaklydriven 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 MultiWave Effects in FastScale LaserPlasma Interactions  2007  School: University of California at Berkeley  
BibTeX:
@phdthesis{Lindberg, author = {Lindberg, R. R.}, title = {Nonlinear and MultiWave Effects in FastScale LaserPlasma Interactions}, school = {University of California at Berkeley}, year = {2007} } 

R. R. Lindberg, A. E. Charman & J. S. Wurtele  Selfconsistent 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 higherorder spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of selfconsistency 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 = {Selfconsistent 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. 727736 

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 multiplepulse 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 = {727736}, 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 BeatWave Accelerator  2004 
Phys. Rev. Lett. Vol. 93 (5), pp. 055001 

Abstract: A modified version of the plasma beatwave 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 BeatWave 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 beatwave 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 phaselocking 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 wavebreaking 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 beatwave 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, ionbeamdriven 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 onaxis 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 lowcost modular fusion drivers and highergain directdrive targets for inertial fusion energy.  
BibTeX:
@article{174265961123032029, 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 JL 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/17426596/112/032029} } 

M. Gullans, J. S. Wurtele, G. Penn & A. Zholents  A source of coherent soft xray radiation based on highorder harmonic generation and free electron lasers  2006  (MOPCH045)  
Abstract: We examine a scheme for a Free Electron Laser (FEL) harmonic amplifier seeded by a 30nm wavelength signal produced using a process of Highorder 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 xray radiation based on highorder harmonic generation and free electron lasers}, year = {2006}, number = {MOPCH045}, note = {Contributed to European Particle Accelerator Conference (EPAC 06), Edinburgh, Scotland, 2630 Jun 2006} } 

M. Harrison, S. D. Holmes, J. M. Paterson & J. S. Wurtele Summer Study on the New Directions in Highenergy 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 postLHC 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 LaserPlasma  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 averagedparticleincell (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 LaserPlasma}, 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{alsharoa20036, 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:hepex/0207031} } 

N. Madsen, G. B. Andresen, M. D. Ashkezari, M. BaqueroRuiz, 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. 716 

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 antiatoms, 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. BaqueroRuiz 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 = {716}, url = {http://rparticle.webp.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=eng&journal=cjp&volume=89&year=2011&issue=1&msno=p10085}, doi = {http://dx.doi.org/10.1139/P10085} } 

V. M. Malkin, N. J. Fisch & J. S. Wurtele  Compression of powerful xray 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 xray pulses. In principle, this method is capable of producing pulse intensities close to the vacuum breakdown threshold by manipulating the output of planned xray 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 xray 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 (23), pp. 109116 

Abstract: It has been proposed that the Raman backscatter interaction in a plasma can be used to amplify ultraintense 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 twodimensional particleincell 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 = {23}, pages = {109116}, url = {http://www.sciencedirect.com/science/article/B6TVM45FSWFK2/1/0e0a1c21dcb909f4ad73ed735f12857f} } 

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 lowenergy 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 onsite detector, as well as to two offsite 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{mcdonald1999, 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  PhaseLocking 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 highQ 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 = {PhaseLocking 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. 39003903 

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 = {39003903}, 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 nonneutral plasmas  1992 
Phys. Rev. Lett. Vol. 69 (21), pp. 30563059 

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 nonneutral plasmas}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1992}, volume = {69}, number = {21}, pages = {30563059}, 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  Highgain free electron lasers using induction linear accelerators  1985 
Quantum Electronics, IEEE Journal of Vol. 21 (7), pp. 831844 

Abstract: Highpower 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 (102104A) at moderately high energy (150 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 highgain, highefficiency 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 = {Highgain free electron lasers using induction linear accelerators}, journal = {Quantum Electronics, IEEE Journal of}, year = {1985}, volume = {21}, number = {7}, pages = {831844} } 

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 highgain freeelectron laser amplifier  1985 
Phys. Rev. Lett. Vol. 54 (9), pp. 889892 

Abstract: A highgain, highextractionefficiency, linearly polarized freeelectron 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 80MW 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 highgain freeelectron laser amplifier}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1985}, volume = {54}, number = {9}, pages = {889892}, 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  HighEfficiency Extraction of Microwave Radiation from a TaperedWiggler FreeElectron Laser  1986 
Phys. Rev. Lett. Vol. 57 (17), pp. 21722175 

Abstract: We have substantially increased the output power and extraction efficiency of a freeelectron laser operating at 34.6 GHz by tapering the wiggler magnetic field. In the exponentialgain regime, the laser exhibited a measured gain of 34 dB/m. With a 50kW input signal, the amplifier saturated in 1.3 m with a 180MW 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 = {HighEfficiency Extraction of Microwave Radiation from a TaperedWiggler FreeElectron Laser}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1986}, volume = {57}, number = {17}, pages = {21722175}, 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. 6184 

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, WH. 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, KY. 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 = {6184}, url = {http://www.sciencedirect.com/science/article/B6TVD3XXDV68W/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{palmer1996372, 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:accphys/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 longlived, nonlinear kinetic structures in a pureelectron plasma. These structures, responsible for largeamplitude 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 onedimensional 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 phasespace 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 twodimensional 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 onedimensional, radially averaged model is derived and implemented in a particleincell 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  Particleincell method for parallel dynamics in magnetized electron plasmas: Study of highamplitude BGK modes  2006 
J. Comp. Phys. Vol. 218 (1), pp. 102122 

Abstract: The present paper describes the numerical technique that has been developed, in the framework of the particleincell (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 longterm evolution of largeamplitude 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 twodimensional phenomena are fully taken into account while keeping the computational effort to that of a standard onedimensional 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 BernsteinGreeneKruskal modes.  
BibTeX:
@article{Peinetti:2006ud, author = {Peinetti, F. and Peano, F. and Coppa, G. and Wurtele, J. S.}, title = {Particleincell method for parallel dynamics in magnetized electron plasmas: Study of highamplitude BGK modes}, journal = {J. Comp. Phys.}, year = {2006}, volume = {218}, number = {1}, pages = {102122}, url = {http://www.sciencedirect.com/science/article/B6WHY4JG48VV2/1/e41a99b3ac88745d0506552cefa60ad0} } 

K. D. Pendergast, B. G. Danley, R. J. Temkin & J. S. Wurtele  Selfconsistent simulation of cyclotron autoresonance maser amplifiers  1988 
Plasma Science, IEEE Transactions on Vol. 16 (2), pp. 122128 

Abstract: A selfconsistent, onedimensional 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 140GHz CARM amplifier with a tapered axial magnetic field and a 700kV 4.5A electron beam with parallel velocity spreads of less than 1%. A discussion of the nonlinear bandwidth and interaction sensitivity to axialfield inhomogeneities is presented  
BibTeX:
@article{3803, author = {Pendergast, K. D. and Danley, B. G. and Temkin, R. J. and Wurtele, J. S.}, title = {Selfconsistent simulation of cyclotron autoresonance maser amplifiers}, journal = {Plasma Science, IEEE Transactions on}, year = {1988}, volume = {16}, number = {2}, pages = {122128}, 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 lowgain 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 lowgain FEL regime, based on trial functions for the output radiation. Full threedimensional 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 xray 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 lowgain 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. 17191722 

Abstract: The Boris push is commonly used in plasma physics simulations because of its speed and stability. It is secondorder 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 fourthorder RungeKutta 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{09543899298337, 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 = {17191722}, url = {http://stacks.iop.org/09543899/29/1719} } 

G. Penn & J. S. Wurtele  Beam Envelope Equations for Cooling of Muons in Solenoid Fields  2000 
Phys. Rev. Lett. Vol. 85 (4), pp. 764767 

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 = {764767}, 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. 30593061 

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 quasiisochronous 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 = {30593061}, 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 ElectroOptics/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 nanosecondlaserpumped 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. Onedimensional particleincell 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 nanosecondlaserpumped 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. BenZvi, 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 (13), pp. 484489 

Abstract: We report first measurements of a singleshot method through which the properties of an electron beam at linac energies may be studied using the spontaneous emission of a microwiggler. 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 BenZvi, 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 = {13}, pages = {484489}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPTFJX8W/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 freeelectron laser  1987 
Physics of Fluids Vol. 30 (7), pp. 22092220 

Abstract: A small signal theory of a freeelectron 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 spacecharge 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 freeelectron laser}, journal = {Physics of Fluids}, publisher = {AIP}, year = {1987}, volume = {30}, number = {7}, pages = {22092220}, 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 FreeElectron Laser  1985 
Phys. Rev. Lett. Vol. 54 (17), pp. 19251928 

Abstract: By use of twodimensional approximations for the equations that describe a highgain freeelectron 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 exponentialgain 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 twodimensional numerical simulations. The phenomenon has applications to shortwavelength 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 FreeElectron Laser}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1985}, volume = {54}, number = {17}, pages = {19251928}, 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. 11771180 

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 higherorder azimuthal modes of the excited electromagnetic fields is derived. Implications of this work for plasmabased 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 = {11771180}, 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. 616629 

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 plasmabased 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 = {616629}, 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. 28882890 

Abstract: Using the Hamiltonian structure of the Vlasov equation, we develop a general, relativistic, threedimensional model of beam transport based on phase space moments of the beam particle distribution. Evolution equations for these moments are derived from the noncanonical Poisson bracket for the Vlasov equation. In this model, the beam centroid experiences the full nonlinear 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 spacecharge 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 = {28882890}, 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, 2226 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. 17161718 

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. Spacecharge 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 sixdimensional 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 6d 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 = {17161718}, 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 threelevel 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 freeelectronlaser amplifier  1997 
Phys. Rev. E Vol. 56 (3), pp. 36063610 

Abstract: We demonstrate how a steadystate train of ultrashort radiation pulses can be produced utilizing a new freeelectron laser (FEL) configuration, the injectionlocked 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 pulsetopulse stability is provided by the prebuncher. 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 ultrashort 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 freeelectronlaser amplifier}, journal = {Phys. Rev. E}, publisher = {American Physical Society}, year = {1997}, volume = {56}, number = {3}, pages = {36063610}, 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 (13), pp. 371375 

Abstract: Theoretical techniques from freeelectron 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 freeelectron 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 particleincell 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 = {13}, pages = {371375}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPTFJX81/1/f7150953fe83b620057629cc6031e22f} } 

G. Shvets & J. S. Wurtele  Pulseshaping in shortpulse FEL oscillators using multiple resonators  1997 
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 393 (13), pp. 237241 

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 = {Pulseshaping in shortpulse 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 = {13}, pages = {237241}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPTFJX70/1/bc77b4832ec2f099b917086886dc7e79} } 

G. Shvets & J. S. Wurtele  Temporal and spectral structure of an FEL oscillator during startup  1997 
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 393 (13), pp. 273276 

Abstract: A previously developed Green's function technique for analyzing the time evolution of lowgain FEL oscillators is applied to the study of the startup 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 startup, 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 startup}, journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, year = {1997}, volume = {393}, number = {13}, pages = {273276}, url = {http://www.sciencedirect.com/science/article/B6TJM3SPTFJX78/1/0a057280ead7eebf4058b20d06ecb697} } 

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 (13), pp. 147150 

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 coworkers [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 = {13}, pages = {147150}, url = {http://www.sciencedirect.com/science/article/B6TJM497C66C1K/1/a81074600cbd9e86338944dc35500e83} } 

G. Shvets & J. S. Wurtele  Green's Function Analysis of Freeelectron Laser Amplifiers ;nd Oscillators  1994  Plasma Science, 1994. Conference Record  Abstracts., 1994 IEEE International Conference on, pp. 201201  
BibTeX:
@article{589081, author = {Shvets, G. and Wurtele, J. S.}, title = {Green's Function Analysis of Freeelectron Laser Amplifiers ;nd Oscillators}, journal = {Plasma Science, 1994. Conference Record  Abstracts., 1994 IEEE International Conference on}, year = {1994}, pages = {201201} } 

G. Shvets & J. S. Wurtele  Instabilities of ShortPulse Laser Propagation through Plasma Channels  1994 
Phys. Rev. Lett. Vol. 73 (26), pp. 35403543 

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 ShortPulse Laser Propagation through Plasma Channels}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {1994}, volume = {73}, number = {26}, pages = {35403543}, doi = {http://dx.doi.org/10.1103/PhysRevLett.73.3540} } 

G. Shvets & J. S. Wurtele  Frequency shifting in freeelectron lasers  1994 
Phys. of Plasma Vol. 1 (1), pp. 157166 

Abstract: Frequency shifting in freeelectron 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 timedependent 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 highpower microwave drivers proposed for high gradient accelerators, where the phase of the radiofrequency radiation is subject to significant constraints. FEL oscillator response to variations in beam energy is examined. It is shown that in a lowgain 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 freeelectron lasers}, journal = {Phys. of Plasma}, publisher = {AIP}, year = {1994}, volume = {1}, number = {1}, pages = {157166}, 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. 351362 

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 stepfunction 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 = {351362}, 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. 681689 

Abstract: Magnetized plasma can be used as an accelerating structure capable of supporting large amplitude longitudinal fields which are externally driven by a highfrequency 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 laserdriven 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 MinSup Hur}, title = {Applications of Magnetized Plasma to Particle Acceleration}, journal = {Advanced Accelerator Concepts: Tenth Workshop}, publisher = {AIP}, year = {2002}, volume = {647}, number = {1}, pages = {681689}, 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. 18721880 

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. Twodimensional 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 = {18721880}, 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. 13071315 

Abstract: The selfconsistent 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 onedimensional approximation, pump depletion is examined for pulsed and steadystate electron beams. A threedimensional 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 = {13071315}, 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 Borislike integration scheme with spatial stepping  2002 
Phys. Rev. ST Accel. Beams Vol. 5 (9), pp. 094001 

Abstract: A modified Borislike integration, in which the spatial coordinate is the independent variable, is derived. This spatialBoris 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 RungeKutta integration scheme. Results from the spatialBoris integration method and a RungeKutta 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 spatialBoris scheme is shown to perfectly conserve for any step size quantities such as the gyroradius and the perpendicular momentum. The RungeKutta 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 spatialBoris integration method is more efficient than a fourthorder RungeKutta scheme. For beam physics applications where statistical quantities such as beam emittance are important, these results imply the spatialBoris 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 Borislike 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  Freeelectron lasers with electromagnetic standing wave wigglers  1987 
Quantum Electronics, IEEE Journal of Vol. 23 (9), pp. 15781589 

Abstract: A detailed analysis of the electromagnetic standing wave wiggler for freeelectron lasers (FEL's) is conducted for both circular and linear wiggler polarizations, following a singleparticle approach. After determination of the unperturbed electron orbits in the wiggler field, the singleparticle 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 selfconsistent 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 = {Freeelectron lasers with electromagnetic standing wave wigglers}, journal = {Quantum Electronics, IEEE Journal of}, year = {1987}, volume = {23}, number = {9}, pages = {15781589} } 

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. 657659 

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 selfconsistent 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 = {657659}, 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. 34033410 

Abstract: An analytic and numerical study of the coupling between a highintensity 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. Onedimensional selfconsistent 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 = {34033410}, 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://wwwmucool.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 19992000 and the Brookhaven Study of 20002001. 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  AllOptical 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 = {AllOptical 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 threewave model to simulate plasmabased backward Raman amplification in one spatial dimension  2009 
Physics of Plasmas Vol. 16 (12), pp. 123110 

Abstract: Results are reported of a onedimensional simulation study comparing the modeling capability of a recently formulated extended threewave 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 particleincell (PIC) code, as well as to a more conventional threewave model, in the context of the plasmabased 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 threewave model performs essentially as well as or better than a conventional threewave description in all temperature regimes tested, and significantly better at the higher temperatures studied, while the computational savings afforded by the extended threewave 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 wideranging 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 threewave model to simulate plasmabased 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} } 

WenHao 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 MuMu 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 = {WenHao 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, 1014 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. 323328 

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 = {323328}, url = {http://www.sciencedirect.com/science/article/B6TJM448YPDG3/1/90782dbb0fa525d637fd4034b18f2ecb} } 

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 xray freeelectron 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 Xray 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 XiaoWei Gu}, title = {Tunable Soft Xray 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. 816839 

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 = {816839}, 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. 23632370 

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 highenergy 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 = {23632370}, 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 antihydrogen in magnetostatic traps: implications for gravitational measurements
[BibTeX] 
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 antihydrogen in magnetostatic traps: implications for gravitational measurements}, journal = {Classical and Quantum Gravity}, year = {2013}, volume = {30}, number = {20}, pages = {205014}, doi = {10.1088/02649381/30/20/205014} } 

J. S. Wurtele, G. Bekefi, R. Chu & K. Xu  Prebunching in a collective Raman freeelectron laser amplifier  1990 
Physics of Fluids B: Plasma Physics Vol. 2 (2), pp. 401406 

Abstract: Experiments, theory, and simulations are reported on the effects of electron prebunching in a mildly relativistic, lowcurrent (200 kV, 1 A) freeelectron 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 freeelectron laser amplifier}, journal = {Physics of Fluids B: Plasma Physics}, publisher = {AIP}, year = {1990}, volume = {2}, number = {2}, pages = {401406}, 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. 16261634 

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 spacecharge 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 spacecharge 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 = {16261634}, 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 laserdriven accelerators for a highenergy linear collider  1997 
Lasers and ElectroOptics, 1997. CLEO '97., Summaries of Papers Presented at the Conference on Vol. 11, pp. 313314 

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 freespace alser and laser/plasma accelerators. It is shown that the requirements impose very severe constraints upon the new acceleratorsso 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 laserdriven accelerators for a highenergy linear collider}, journal = {Lasers and ElectroOptics, 1997. CLEO '97., Summaries of Papers Presented at the Conference on}, year = {1997}, volume = {11}, pages = {313314} } 

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 threewave 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 phaselocked 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 plasmabased 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. 462468 

BibTeX:
@article{YuBackhaus: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 = {462468}, url = {http://www.sciencedirect.com/science/article/B6WHY45J58X03J/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. 33273329 

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 = {33273329}, 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. 33993401 

Abstract: A formalism is developed for the analysis of collective instabilities in standingwave systems. The analysis permits a unified treatment of the coupledcavity freeelectron 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 = {33993401}, doi = {http://dx.doi.org/10.1109/PAC.1993.309663} } 