Statistical survey on the magnetic field in magnetotail current sheets: Cluster observations  

作　　者：RONG ZhaoJin SHEN Chao LUCEK E BALOGH A YAO Li 

机构地区：[1]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China [3]College of Earth Science, Graduate University of Chinese Academy of Sciences, Beijing 100049, China [4]Imperial College, London SW7 2AZ, United Kingdom

出　　处：《Chinese Science Bulletin》2010年第23期2542-2547,共6页

基　　金：supported by the National Natural Science Foundation of China (40621003 and 40674094);the National Basic Research Program of China (2006CB806305);the Hundred Talents Program of the Chinese Academy of Sciences,and the Specialized Research Fund for State Key Laboratories

摘　　要：The distribution properties of the magnetic field in magnetotail current sheets have been explored statistically with the magnetic measurement data of the Cluster mission from June to November of the years 2001–2005.It is found that,on average,the strength of the magnetic field and its Bz component in the current sheet are weaker in the region close to midnight but stronger near the dawnside and duskside flanks,which implies that,in general,a thinner current sheet occurs near midnight and thicker ones near both flanks.The occurrence of tail current sheet flapping is higher on both flanks than in the midnight region,although it is most frequent in the dawn flank.Current sheets with a negative Bz component or a strong By component have a higher probability of occurring at magnetic local times of 21:00–01:00,indicating that magnetic activity,e.g.magnetic reconnection and current disruption occur more frequently there.Statistically,the probability distributions of the By component and the tilt angle of magnetic field lines in the current sheet are approximately normal distributions,and the occurrence probability of the flattened current sheet is about one third that of the normal current sheet.The magnetic field and Bz component in the current sheet mainly vary from 1 nT to 10 nT.The By component in the tail central current sheet is on average twice the IMF By at 1 AU.The distribution properties of the magnetic field in magnetotail current sheets have been explored statistically with the magnetic measurement data of the Cluster mission from June to November of the years 2001 2005. It is found that, on average, the strength of the magnetic field and its Bz component in the current sheet are weaker in the region close to midnight but stronger near the dawnside and duskside flanks, which implies that, in general, a thinner current sheet occurs near midnight and thicker ones near both flanks. The occurrence of tail current sheet flapping is higher on both flanks than in the midnight region, although it is most frequent in the dawn flank. Current sheets with a negative Bz component or a strong By component have a higher probability of occurring at magnetic local times of 21：00M）1：00, indicating that magnetic activity, e.g. magnetic reconnection and current disruption occur more frequently there. Statistically, the probability distributions of the By component and the tilt angle of magnetic field lines in the current sheet are approximately normal distributions, and the occurrence probability of the flattened current sheet is about one third that of the normal current sheet. The magnetic field and Bz component in the current sheet mainly vary from 1 nT to 10 nT. The By component in the tail central current sheet is on average twice the IMF By at 1 AU.

关 键 词：统计调查 磁场分布 电流片 集群 磁尾 国际货币基金组织 概率分布 倾斜角度 

分 类 号：O212.2[理学—概率论与数理统计] O441.4[理学—数学]