Ultra-low emittance beam generation using two-color ionization injection in a CO2 laser-driven plasma accelerator

Schroeder, Carl¹  Benedetti, Carlo¹  Bulanov, Stepan¹  Chen, Min²  Esarey, Eric¹  Geddes, Cameron¹  Vay, J.¹  Yu, Lule²  Leemans, Wim¹ 

[1] Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States);Shanghai Jiao Tong Univ. (China)

关键词: CARBON DIOXIDE LASERS;    ELECTRON BEAMS;    INJECTION;    COLOR;    ELECTRONS;    IONIZATION;    PLASMA GUNS;    TRAPPING;    BEAM EMITTANCE;    DISTRIBUTION;    POLARIZATION;    RUBY LASERS;    WAKEFIELD ACCELERATORS;   

DOI  :  10.2172/1233743
RP-ID  :  LBNL--179526
PID  :  OSTI ID: 1233743
Others  :  Other: ir:179526
Others  :  TRN: US1600208

学科分类：核物理和高能物理

美国|英语

来源: SciTech Connect

【 摘 要 】

Ultra-low emittance (tens of nm) beams can be generated in a plasma accelerator using ionization injection of electrons into a wakefield. An all-optical method of beam generation uses two laser pulses of different colors. A long-wavelength drive laser pulse (with a large ponderomotive force and small peak electric field) is used to excite a large wakefield without fully ionizing a gas, and a short-wavelength injection laser pulse (with a small ponderomotive force and large peak electric field), co-propagating and delayed with respect to the pump laser, to ionize a fraction of the remaining bound electrons at a trapped wake phase, generating an electron beam that is accelerated in the wake. The trapping condition, the ionized electron distribution, and the trapped bunch dynamics are discussed. Expressions for the beam transverse emittance, parallel and orthogonal to the ionization laser polarization, are presented. An example is shown using a 10-micron CO₂ laser to drive the wake and a frequency-doubled Ti:Al₂O₃ laser for ionization injection.