基于VAP卫星的等离子体层顶电子密度波动统计分析  

A statistical analysis of the electron number density fluctuations near the plasmapause based on Van Allen Probes observations

作　　者：王玉尤婷 张效信[2] 何飞 林瑞淋 吕景天 WANG YuYouTing;ZHANG XiaoXin;HE Fei;LIN RuiLin;Lü JingTian(Chinese Academy of Meteorological Sciences,Beijing 100081,China;Key Laboratory of Space Weather,National Center for Space Weather,China Meteorological Administration,Beijing 100081,China;Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]中国气象科学研究院,北京100081 [2]国家卫星气象中心空间天气重点开放实验室,北京100081 [3]中国科学院地球与行星物理重点实验室,中国科学院地质与地球物理研究所,北京100029 [4]中国科学院国家空间科学中心,北京100190

出　　处：《地球物理学报》2020年第6期2141-2148,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41774152,41931073)资助.

摘　　要：基于范艾伦辐射带探测卫星的观测数据(2012年9月至2015年11月),收集了584个等离子体层顶密度波动事件,研究了这些事件分布随磁地方时、磁壳值以及地磁活动的变化关系,并使用快速傅里叶变换分析了全部事件平均功率谱.统计结果表明,等离子体层顶密度波动事件主要发生在磁地方时黄昏扇区,其分布与磁地方时和地磁活动具有明显的相关性.等离子体层顶密度波动在1~100mHz区间内具有接近-5/3的功率谱斜率,表明存在二维磁流体动力学湍流.本文统计结果将有助于进一步深入理解等离子体层顶密度波动在内磁层中能量传输的具体作用,并且将促进对等离子体层顶波动的激发、增强与传播过程的进一步研究.Based on observations(September 2012 to November 2015)from the Van Allen Probes(VAP),584 plasmapause density fluctuation events are collected.The electron density deduced from the high frequency receiver is used to calculate the wave spectrum at different magnetic local time(MLT),L-shell,and geomagnetic activity.Statistical results show that the electron density fluctuation events at the plasmapause mainly occur in the twilight sectors and the spatial distribution varies with MLT and geomagnetic activity.The power spectral density of the plasmapause electron density fluctuations has a slope of-5/3 between 1 mHz and 100 mHz,indicating the presence of two-dimensional magnetohydrodynamic turbulence.The above results will shed light on further understanding of the specific role of density fluctuations on the energy transfer near the plasmapause,and will further promote researches on the excitation,enhancement and propagation of the plasmapause fluctuations.

关 键 词：等离子体层顶 密度波动 统计分析 平均功率谱 快速傅里叶变换 

分 类 号：P354[天文地球—空间物理学]