关键词: 激光电子加速/
电离注入/
相空间/
宽能谱
English Abstract
Generation of ultrafast broadband small angle hundreds MeV electron bunches from laser wakefield acceleration
Li Rong-Feng1,Gao Shu-Chao1,
Xiao Chao-Fan1,
Xu Zhi-Yi1,
Xue Xing-Tai1,
Liu Jian-Bo1,
Zhao Yan-Ying1,
Chen Jia-Er1,
Lu Hai-Yang1,2,
Yan Xue-Qing1,2
1.State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China;
2.Center for Applied Physics and Technology, Peking University, Beijing 100871, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant No.11575011),the National Grand Instrument Project,China (Grant No.2012YQ030142),and the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No.SQ2016ZY04003194).Received Date:05 April 2017
Accepted Date:11 May 2017
Published Online:05 August 2017
Abstract:Electrons can be accelerated to a GeV level in centimeters by plasma wakefield driven by laser. With the development of chirped pulse amplification technique, the accelerating field can reach 100 GV/m. The laser driven wakefield acceleration experiments with ionization injection are carried out using 68 TW (1.7 J, 25 fs) laser and a mixture gas of 99% He and 1% N2. In experiment, the output electron beam has broadband spectrum with a maximum cut-off energy of about 290 MeV and a maximum output energy is quite stable in a certain range of laser focal positions. Two-dimensional particle-in-cell simulation is carried out. It is found that the longitudinal phase space is occupied by the continuously injected electrons and the phase space distribution is quite stable after the laser has propagated several millimeters inside plasma. This acceleration process can lead to quite stable maximum output energy of electron beam. These experiments reveal the physical nature of continuous ionization injection, which is very important for improving the performance of ionization injection.
Keywords: laser driven wakefield acceleration/
ionization injection/
phase space/
large energy-spread
