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Particle acceleration in the magnetotail associated with magnetospheric substorms and storms

与磁层亚暴和风暴相关的磁尾中的粒子加速

基本信息

批准号：
07640587
负责人：
NAKAMURA Rumi
金额：
$ 1.28万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640587/
关键词：
Magnetospheric structure Magnetic storm Magnetospheric magnetic field Boundary Layr High energy particles Radiation belt Inner magnetosphere Magnetotail 降下粒子

项目摘要

1. We discuss the radial evolution of the fast flow in the tail associated with substorm based on statistical studies using GEOTAIL magnetic field and plasma data. While the tailward flow has a systematic tailward and spatial evolution, where a typical timescale 20-30 minutes can be identified, the earthward flow is differs from event to event.2. Changes in the structure of the distant tail associated with geomagnetic storms are studied by using plasma and magnetic field data obtained from GEOTAIL.Thirteen storm intervals between October 1993 and October 1994 are examined when the satellite was located in the distant tail between X=-83R_Eand*=-210R_E. GEOTAIL observed the magnetosheath during all storms including those when the satellite was located near the nomianl tail axis. It is found that an average energy of -5x 10^<15>J is stored also in the distant tail during the storm main phase, which is a comparable value to that stored in the midtail during an intense substorm growth phase reported in the previous studies.3. We studied flux variations in the outer radiation belt electrons during main phase and early recovery phase of geomagnetic storm using data obtained by SAMPEX.We examined 25 well defined storms with different activity level. By comparing with a simple model of ring current magnetic field perturbations, it is shown that the decrease is attributed to the adiabatic deceleration in response to the storm time magnetic field due to ring current particle. Such adiabatic response in most clearly detected between L=4-5, at the center of the 1 MeV radiation belt, and where the magnetic perturbation due to the ring current could have largest effect.

1.利用GEOTAIL磁场和等离子体资料，通过统计研究，讨论了与亚暴相关的尾部快速流的径向演化。虽然尾流有一个系统的尾流和空间演变，其中一个典型的时间尺度20-30分钟可以确定，地球流是不同的事件。本文利用GEOTAIL卫星的等离子体和磁场资料，研究了1993年10月至1994年10月间13个磁暴间隔中与磁暴有关的远尾结构的变化。GEOTAIL在所有风暴期间都观测到了磁鞘，包括当卫星位于名义尾轴附近时。发现在<15>风暴主相期间，远尾也储存了-5x10 ^ J的平均能量，这与以前研究报道的强亚暴增长阶段中尾储存的能量相当.利用SAMPEX观测资料，研究了磁暴主相和恢复初期外辐射带电子通量的变化，共观测了25个不同活动水平的磁暴。通过与环电流磁场扰动的简单模型的比较，表明这种减小是由于环电流粒子对暴时磁场的绝热减速。这种绝热响应在L=4-5之间最清楚地检测到，在1 MeV辐射带的中心，并且由于环电流引起的磁扰动可能具有最大的影响。