哨声模合声波与地球同步轨道高能电子通量增强事件事例研究  

Study on High Energy Electron Flux Enhancement Events and Whistler Chorus Wave

作　　者：何甜[1,2] 刘四清[1] 郑金磊[1,2] 龚建村[1] 

机构地区：[1]中国科学院空间科学与应用研究中心,北京100190 [2]中国科学院大学,北京100049

出　　处：《空间科学学报》2013年第2期170-175,共6页Chinese Journal of Space Science

基　　金：国家重点基础研究发展计划项目资助(2012CB825606)

摘　　要：局部加速机制是磁暴期间地球外辐射带高能电子通量增强事件发生的重要原因.此加速机制需要两个基本条件,一是存在种子电子,二是存在能与种子电子产生共振的加速波动,包括哨声模合声波.通过对2004—2006年Pi1地磁脉动持续时间与种子电子通量的相关性分析,更明确提出Pi1地磁脉动的持续时间可以作为种子电子通量的指示剂.通过对三个磁暴事例地球同步轨道的种子电子通量、高能电子通量及哨声模合声波变化情况的分析,发现在高能电子通量较强的事例中,均观测到较高的种子电子通量和较强的哨声模合声波,这在一定程度上验证了哨声模合声波对种子电子的回旋加速机制,且合声波强度与高能电子通量有正的相关性.The local acceleration mechanism is one of the crucial factors for the high energy electron flux enhancement events in the outer radiation belt. There are two substantial preconditions for this acceleration mechanism. The first and the most important one is the presence of enough low energy electron （on the order of tens to hundreds of keV）, so-called seed electron; the other is the enhancement of plasma waves including whistler chorus waves which can contribute to the electron acceleration by wave-particle interaction. Geomagnetic field data observed by Memambetsu （L -- 1.57） observatory are used to extract Pil pulsation during 2004--2006. The linear correlation between Pil pulsation duration and seed electron flux （LANL 50-225 keV） is greater than 0.7, which indicates that the Pil pulsation duration is a good indicator of seed electron flux. After the investigation of three magnetic storms events in 2005, the evidence had been found for acceleration of seed electrons to high energies by whistler chorus waves and the positive correlation between the chorus waves＇ spectral density and high energy electron flux.

关 键 词：地球同步轨道 高能电子通量 哨声模合声波 地磁脉动 

分 类 号：P318[天文地球—固体地球物理学]