基于混合注入机制的级联尾场电子加速  

Mixed injection mechanism assisted cascaded laser wakefield accelerator

作　　者：谭放 张晓辉[2] 朱斌 李纲[2] 吴玉迟[2] 于明海[2] 杨月 闫永宏[2] 杨靖[2] 范伟[2] 董克攻[2] 卢峰[2] 谷渝秋[2] Tan Fang;Zhang Xiao-Hui;Zhu Bin;Li Gang;Wu Yu-Chi;Yu Ming-Hai;Yang Yue;Yan Yong-Hong;Yang Jing;Fan Wei;Dong Ke-Gong;Lu Feng;Gu Yu-Qiu(Institute of Modern Physics, University of Science and Technology of China, Hefei 030006, China;Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center,China Academy of Engineering Physics, Mianyang 621900, China)

机构地区：[1]中国科学技术大学近代物理系,合肥030006 [2]中国工程物理研究院激光聚变研究中心,高温高密度等离子体物理国家重点实验室,绵阳621900

出　　处：《物理学报》2019年第17期189-197,共9页Acta Physica Sinica

基　　金：中国工程物理研究院院长基金(批准号:2014-01-17);国家自然科学基金委员会-中国工程物理研究院联合基金(批准号:U1630246);国防基础科研核基础科学挑战专题高能量密度科学领域(批准号:JCKY2016212A505);国家重点研发计划(批准号:016YFA0401100)资助的课题~~

摘　　要：激光尾场电子加速装置中,为了获得可稳定重复产生的高质量单能尾场电子,电子的可控注入是其中的关键.基于自主设计的级联加速喷气靶,研究离化注入、冲击波前沿注入等可控注入技术及其结合对尾场电子产生阈值、电子能谱及其稳定性的影响.研究结果显示,离化注入机制、冲击波前沿注入机制以及级联加速喷嘴的结合,可以使尾场电子的注入阈值大幅度降低,且电子的离化注入区域被限制于冲击波前沿处,最终大幅度降低电子束的绝对能散、提高稳定性.在最优化的条件下,可以获得最小发散角为(3.6×3.8)mrad,平均中心能量为(63.24±6.12)MeV,平均能散为(13.0±3.9)MeV、平均电量为(5.99±3.10)pC的重频单能尾场电子.Femtosecond electron bunches can be produced by laser plasma wakefield accelerators,with energy tuna.ble from tens of MeV to a few GeV.In order to produce stable mono-energetic electron bunches,a critical issue is to control the injection of electron into the wakefield.The ionization injection is one of the most effective methods of controlling the injection,which is usually a continuous process.So,the electron bunches produced through ionization injection usually possess large energy spread.In order to optimize the ionization injection technique and produce sta.ble monoenergetic wakefield electron beams,experimental studies are conducted on our 45 TW laser facility.In this work,a mixed injection mechanism assisted cascaded laser wakefield accelerator is presented.Based on a double-nozzle cascaded accelerator,the influences of ionization injection,shock wave front injection and their combination are experimentally studied.The results show that the lower threshold of the injection can be substantially reduced.The ionization injection is restricted within the shock wave front.As a result,mono-energetic electron bunches with reduced absolute energy spread can be stably produced.Under the most optimal conditions,the central energy and energy spread are(63.24 ±6.12)MeV and(13.0 ±3.9)MeV.The charge quantity of the electron bunches is(5.99±3.10)pC.The minimum emitting anglular spread is(3.6 × 3.8)mrad.

关 键 词：尾场加速 级联加速 冲击前沿注入 离化注入 

分 类 号：TL50[核科学技术—核技术及应用]