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Studies on magnetospheric boundary processes based on magnetic field and aurora observation in the northern and southern polar caps

基于磁场和极光观测的南北极磁层边界过程研究

基本信息

批准号：
12573007
负责人：
FUKUNISHI Hiroshi
金额：
$ 9.41万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

In order to clarify the interaction between the solar wind and the magnetosphere of the Earth, magnetospheric boundary processes were investigated, making use of 6 non-manned automatic geophysical observatories (AGO) located in the interior of the Antarctic Continent. Comprehensive analysis was carried out, combining data recorded by AGO equipments, such as magnetometers, aurora imagers, riometers and VLF receivers, and solar wind and solar activity data obtained by spacecrafts as well as HF radar data at Syowa station. Results including some important and new findings are as follows:1) Conjugate TCV (traveling convection vortices) events moving sunward in both hemispheres were found and its physical mechanisms were investigated in detail.2) Transient ionospheric disturbances relating to the TCV were found. It is shown that the disturbances are consequence of non-linear processes in F-region caused by 3-D current system and auroral particle precipitations.3) Automatic detection algorithms for MIE (magnetic impulse event) and for TD (tangential discontinuity) were developed successfully.Using these algorithms,it was found that occurences of MIE and TD show correlation in seasonal variation.4) A tecchnique to calculate the TD arrival time using data obtained by one spacecraft was developed.5) Quantitative model for TCV phenomena considering conjugate condition in the magnetosphere-ionosphere coupling processes was constructed.6) 3-D MHD simulation was conducted to understand the current generation mechanisms associated with TCV. The results succeeded in reproducing typical TCV phenomena.

为了阐明太阳风与地球磁层之间的相互作用，利用位于南极大陆内部的6个无人自动地球物理观测站（AGO）对磁层边界过程进行了研究。结合地磁仪、极光成像仪、转速仪、VLF接收机等AGO设备记录的数据，结合航天器获取的太阳风和太阳活动数据以及Syowa站高频雷达数据，进行综合分析。结果包括一些重要的新发现：1)在两个半球发现了向太阳运动的共轭对流涡旋（TCV）事件，并对其物理机制进行了详细的研究。2)发现了与TCV有关的瞬态电离层扰动。结果表明，这些扰动是三维电流系统和极光粒子沉降引起的f区非线性过程的结果。3)成功开发了磁脉冲事件（MIE）和切向不连续（TD）的自动检测算法。利用这些算法，发现MIE和TD的发生在季节变化中具有相关性。4)提出了一种利用单航天器数据计算TD到达时间的方法。5)建立了磁层-电离层耦合过程中考虑共轭条件的TCV定量模型。6)通过三维MHD模拟，了解TCV的当前生成机制。结果成功再现了典型的TCV现象。