地球磁尾等离子体片磁洞的统计分析  

The statistical analysis on magnetic holes inside the Earth magnetotail plasma sheet

作　　者：刘建坤[1] 葛亚松[2] 张铁龙[1,3] 王国强[1] LYU Hao-Yu 

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026 [2]中国科学院地质与地球物理研究所,北京100029 [3]奥地利科学院空间研究所 [4]北京航空航天大学空间与环境学院,北京100191

出　　处：《地球物理学报》2017年第3期873-878,共6页Chinese Journal of Geophysics

基　　金：国家自然科学基金面上项目(41474144和41574173);THEMIS计划由美国NASA基金(NAS5-02099)资助

摘　　要：本文利用THEMIS卫星的磁场数据和等离子体观测数据,统计分析地球磁尾等离子体片区域线性磁洞的发生率、时空尺度、分布特征、和发生率与地磁AE指数的相关性.分析结果表明磁尾等离子体片区域的磁洞的时间尺度为几秒到几十秒,空间尺度小于当地的质子回旋半径.通过磁洞在空间的位置分布和卫星数据在空间的数据采样分布的对比,我们发现线性磁洞在等离子体片内经常发生,然而在磁尾等离子体片中的发生率要小于太阳风中磁洞的发生率.本文最后统计分析了磁洞发生和AE指数的相关性,结果表明磁洞可能与地磁活动有关系.In this study we investigate the statistical properties of linear magnetic holes inside the Earth magnetotail plasma sheet region, including the occurrence rate, the temporal and spatial scales, the spatial distribution and the correlation between the occurrence rate and AE index, by using THEMIS satellites magnetic field and plasma data for this paper. Our results indicate that the time scale of the magnetic holes inside the magnetotail plasma sheet region varies from several seconds to tens of seconds, and the spatial scale is smaller than the local proton gyro-radius. We compare the spatial distribution of satellite observations with the spatial distribution of magnetic holes. The results suggest that linear magnetic holes are often observed in the plasma sheet, while the occurrence rate is significantly lower than that of magnetic holes in the solar wind. We also analyze the correlation of the AE index with magnetic holes, and find that magnetic holes occurrence may be associated with the geomagnetic activity.

关 键 词：磁洞 磁尾等离子体片 THEMIS卫星 AE指数 

分 类 号：P353[天文地球—空间物理学]