激光驱动磁重联过程中的喷流演化和电子能谱测量  

Measurement of jet evolution and electron energy spectrum during the process of laser-driven magnetic reconnection

作　　者：张凯[1,2] 仲佳勇 裴晓星[1,2] 李玉同[4] 阪和洋一 魏会冈[1] 袁大伟 李芳[4] 韩波[1] 王琛[6] 贺昊[6] 尹传磊[4] 廖国前 方远[7] 杨骕[7] 远晓辉[7] 梁贵云[1] 王菲鹿[1] 朱健强[8] 丁永坤[9] 张杰 赵刚[1] 

机构地区：[1]中国科学院光学天文重点实验室(国家天文台),北京100012 [2]中国科学院大学,北京100049 [3]北京师范大学天文系,北京100875 [4]中国科学院物理研究所,北京100190 [5]大阪大学激光工程研究所 [6]中国工程物理研究院上海激光等离子体研究所,上海201800 [7]上海交通大学物理学院,上海200240 [8]高功率激光物理联合实验室,上海201800 [9]中国工程物理研究院激光聚变研究中心,绵阳621900

出　　处：《物理学报》2015年第16期317-323,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2013CBA01503);国家自然科学基金(批准号:11205015;11273033;11135012);北京科技新星(批准号:Z131109000413050)资助的课题~~

摘　　要：利用神光Ⅱ激光器和日本大阪大学Gekko激光器构建了激光驱动等离子体磁重联过程.在垂直于磁重联平面方向发现了高速喷流,从不同观测方向实验证实了该喷流的存在并测量了喷流的流体力学演化过程,对其中的电子能谱进行了诊断分析.Magnetic reconnection （MR） is a universal physical process in plasma, in which the stored magnetic energy is converted into high-velocity flows and energetic particles. It is believed that MR plays an important role in many plasma phenomena such as solar fare, gamma-ray burst, fusion plasma instabilities, etc.. The process of MR has been studied in detail by dedicated magnetic-driven experiments. Here, we report the measurements of magnetic reconnection driven by Shenguang II lasers and Gekko XVII lasers. A collimated plasma jet is observed along the direction perpendicular to the reconnection plane with the optical probing. The present jet is very different from traditional magnetic reconnection outflows as known in the two-dimensional reconnection plane. In our experiment, by changing the delay of optical probing beam, we measure the temporal evolution of jet from 0.5 ns to 2.5 ns and its velocity around 400 km/s is deduced. High- collimated jet is also confirmed by its strong X-ray radiation recorded by an X-ray pinhole camera. With the help of optical interferograms we calculate the jet configuration and its density distribution by using Abel inverting technique. A magnetic spectrometer with an energy range from hundred eV up to one MeV is installed in front of the jet, in the direction perpendicular to the reconnection plane, to measure the accelerated electrons. Two cases are considered for checking the acceleration of electrons. The results show that more accelerated electrons can be found in the reconnectioncase than in the case without reconnection. We propose that the formation and collimation of the plasma jet, and the electron energy spectrum may be possible directly influenced by the reconnection electric field, which is very important for understanding the energy conversion in the process of MR and establishment of the theoretical model. Finally the electron energy spectra of three different materials A1, Ta and Au are also shown in our work. The results indicate that the higher atomic number ma

关 键 词：磁重联 电子加速 

分 类 号：TN248[电子电信—物理电子学]