Magnetotail dipolarization fronts and particle acceleration:A review  

作　　者：Huishan FU Elena EGRIGORENKO Christine GABRIELSE Chengming LIU San LU KJHWANG Xuzhi ZHOU Zhe WANG Fang CHEN 

机构地区：[1]School of Space and Environment,Beihang University,Beijing 102206,China [2]Space Research Institute of RAS,Moscow,Russia [3]Earth,Planetary,and Space Sciences Department,University of California,Los Angeles,USA [4]Southwest Research Institute,San Antonio,USA [5]Institute of Space Physics and Applied Technology,Peking University,Beijing 100871,China

出　　处：《Science China Earth Sciences》2020年第2期235-256,共22页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41404133, 41874188, 41574153, 40621003 & 41431071);supported by the project (Grant No. KP19-270);Christine GABRIELSE was supported by NASA (Grant No. NAS5-02099);the support by NASA’s MMS project at Sw RI and NSF (Grant Nos. AGS1602510, NASA NNX16AI39G/80NSSC18K1534, 80NSSC18K0570 & 80NSSC18K0693)

摘　　要：In this paper, the particle acceleration processes around magnetotail dipolarization fronts(DFs) were reviewed. We summarize the spacecraft observations(including Cluster, THEMIS, MMS) and numerical simulations(including MHD, testparticle, hybrid, LSK, PIC) of these processes. Specifically, we(1) introduce the properties of DFs at MHD scale, ion scale, and electron scale,(2) review the properties of suprathermal electrons with particular focus on the pitch-angle distributions,(3)define the particle-acceleration process and distinguish it from the particle-heating process,(4) identify the particle-acceleration process from spacecraft measurements of energy fluxes, and(5) quantify the acceleration efficiency and compare it with other processes in the magnetosphere(e.g., magnetic reconnection and radiation-belt acceleration processes). We focus on both the acceleration of electrons and ions(including light ions and heavy ions). Regarding electron acceleration, we introduce Fermi,betatron, and non-adiabatic acceleration mechanisms;regarding ion acceleration, we present Fermi, betatron, reflection, resonance, and non-adiabatic acceleration mechanisms. We also discuss the unsolved problems and open questions relevant to this topic, and suggest directions for future studies.In this paper, the particle acceleration processes around magnetotail dipolarization fronts(DFs) were reviewed. We summarize the spacecraft observations(including Cluster, THEMIS, MMS) and numerical simulations(including MHD, testparticle, hybrid, LSK, PIC) of these processes. Specifically, we(1) introduce the properties of DFs at MHD scale, ion scale, and electron scale,(2) review the properties of suprathermal electrons with particular focus on the pitch-angle distributions,(3)define the particle-acceleration process and distinguish it from the particle-heating process,(4) identify the particle-acceleration process from spacecraft measurements of energy fluxes, and(5) quantify the acceleration efficiency and compare it with other processes in the magnetosphere(e.g., magnetic reconnection and radiation-belt acceleration processes). We focus on both the acceleration of electrons and ions(including light ions and heavy ions). Regarding electron acceleration, we introduce Fermi,betatron, and non-adiabatic acceleration mechanisms; regarding ion acceleration, we present Fermi, betatron, reflection, resonance, and non-adiabatic acceleration mechanisms. We also discuss the unsolved problems and open questions relevant to this topic, and suggest directions for future studies.

关 键 词：Dipolarization front Electron acceleration Ion acceleration Magnetic reconnection REVIEW Reconnection front 

分 类 号：V525[航空宇航科学与技术—人机与环境工程]