行星际激波导致的磁尾等离子片中ULF波动事件  

ULF Wave in the Magnetotail Plasma Sheet Induced by Interplanetary Shock

作　　者：宋小健 左平兵 沈晓晨 SONG Xiaojian;ZUO Pingbing;SHEN Xiaochen(National Space Science Center,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049;Institute of Space Science and Applied Technology,Harbin Institute of Technology,Shenzhen 518055;Center for Space Physics,Boston University,Boston 02215)

机构地区：[1]中国科学院国家空间科学中心,北京100190 [2]中国科学院大学,北京100049 [3]哈尔滨工业大学(深圳)空间科学与应用技术研究院,深圳518055 [4]波士顿大学空间物理中心,波士顿02215

出　　处：《空间科学学报》2020年第4期462-470,共9页Chinese Journal of Space Science

基　　金：国家自然科学基金项目(41731067);深圳市科创委基础研究项目(JCYJ20180306171748011)共同资助。

摘　　要：磁层中的超低频(ULF)波动在太阳凤和磁层之间的能量输运过程中具有重要作用.ULF波动主要发生在内磁层,且内磁层中ULF波动影响粒子的加速及沉降,而在夜侧磁层尤其是磁尾等离子片中观测到的ULF波动比较少.基于中国自主磁层探测卫星TC-1的观测数据,发现了两例行星际激波导致的磁尾中心等离子片中ULF波动事件,并发现这两例ULF事例都包含很强的环向模驻波分量,与以往THEMIS卫星报道的同类事件观测特征相符.根据ULF波的观测特征,分析了这两例ULF波动的可能触发机制.研究结果有助于深入理解磁层对行星际激波的全球响应.Ultra Low Frequency(ULF)waves play an important role in energy transport from the solar wind into the magnetosphere.The ULF waves have often been observed in the dayside magnetosphere,which affects the acceleration and deceleration of energetic particles in inner magnetosphere,and is also responsible for the particle precipitation.There have been few reports of ULF wave activity on the nightside.Here based on the observations of TC-1 in the magnetotail central plasma sheet,two ULF wave events induced by two interplanetary shocks are identified and analyzed.East-west magnetic and radial electric field perturbations,which denote the toroidal mode,are found to be stronger for the two cases and their phase difference are nearly 90°.These features are consistent with previous observations from THEMIS.Several possible mechanisms for these kinds of ULF wave excitation are discussed according to the observational characteristics.It helps to deepen the understanding of the global response of the magnetosphere to interplanetary shocks.

关 键 词：磁尾等离子片 ULF波动 环向模 行星际激波 

分 类 号：P353[天文地球—空间物理学]