Ion flux dropout observed near dipolarization front

作     者：Xueling Shi Tao Chen Lingqian Zhang Suping Duan Jiang Liu Zhaohai He 

作者机构：State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Department of Earth Planetary and Space Sciences Institute of Geophysics and Planetary Physics University of California Los Angeles CA 90095 USA 

出 版 物：《Chinese Science Bulletin》 (Chinese Science Bulletin)

年 卷 期：2014年第59卷第8期

页      面：4790-4796页

核心收录：

学科分类：070802[理学-空间物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：supported by the National Natural Science Foundation of China(40774081) Ministry of Science and Technology of China(2011CB811404) the Specialized Research Fund for State Key Laboratories 

主　　题：能量通量 离子流 双极化 观测 等离子体片 总谐波失真 THC 空间范围 

摘      要：An ion flux dropout near the dipolarization front(DF) at around XGSM=-11 REin the Earth s plasma sheet was observed by Time History of Events and Macroscale Interaction during substorms(THEMIS) on March31, 2009. The ion differential energy fluxes at energies from 450 e V to 150 ke V measured by the ESA and SST instruments from THC began to decrease about 2 s before the detection of the DF and reached a local minimum 6 s later. Then, the ion fluxes gradually increased to form a dropout around the DF. The spatial extent of the dropout was about 4,000 km. For energies above 20 ke V, the ion fluxes after the dropout are greater than those before it,contrary to the fluxes at energies below 20 ke V. The associated ion density variation indicates that the ion flux dropout coincides with the ion density dropout. Taking advantage of multipoint observations, THD, THC, and THE detected the same DF consecutively. Only THC detected an obvious ion flux dropout; THD observed an indistinct one about 2 s before THC; no high-energy(E [ 30 ke V) ion flux dropout was observed by THE. Our study suggests that the ion flux dropout may evolve withthe earthward-propagating DF, and its properties can depend on locations relative to the DF.