Laboratory observation of electron energy distribution near three-dimensional magnetic nulls  

作　　者：何任川 徐田超 杨肖易 肖池阶 张祖煜 袁瑞鑫 王晓钢 郭志彬 余修铭 盖跃 Renchuan HE;Tianchao XU;Xiaoyi YANG;Chijie XIAO;Zuyu ZHANG;Ruixin YUAN;Xiaogang WANG;Zhibin GUO;Xiuming YU;Yue GE(State Key Laboratory of Nuclear Physics and Technology,School of Physics,Peking University,Beijing 100871,People's Republic of China;Department of Physics,Harbin Institute of Technology,Harbin 150001,People's Republic of China)

机构地区：[1]State Key Laboratory of Nuclear Physics and Technology,School of Physics,Peking University,Beijing 100871,People's Republic of China [2]Department of Physics,Harbin Institute of Technology,Harbin 150001,People's Republic of China

出　　处：《Plasma Science and Technology》2024年第3期46-52,共7页等离子体科学和技术（英文版）

基　　金：supported by National Natural Science Foundation of China(No.11975038);the National Key Research and Development Program of China(No.2022YFA1604600)。

摘　　要：The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection process.To explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic nulls.This study measured the plasma floating potential and ion density profiles around the 3D magnetic null.The potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial positions.The axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic nulls.With scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null topology.The kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.

关 键 词：electron acceleration EEDF 3D magnetic null magnetic reconnection 

分 类 号：O441[理学—电磁学]