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Coupling of magnetospheric and field-aligned currents by satellite-based observations

通过卫星观测耦合磁层和场对准电流

基本信息

批准号：
01540348
负责人：
IIJIMA Takesi
金额：
$ 1.15万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01540348/
关键词：
Region 1 field-aligned current Region 2 field-aligned current Magnetospheric ring current Magnetospheric radial current Precipitating ion core part Precipitating ion explosive part Field-aligned ion flow Magnetopsheric boundary layer 磁気圏堺界

项目摘要

Electric current flowing in the near-equatorial magnetosphere(L--4-9 R_E)consists of two basic elements : azimuthal current and radial current. Azimuthal current flows westward around the earth. Radial current flows toward the earth in the late-evening to premidnight sector and away from the earth in the midnight to early-morning sector.Presence of magnetospheric radial current is consistent with the counter current of ionosphere Pedersen current at auroral latitudes that is projected in the magnetospheric equatorial plane.Inhomogenuity in azimuthal and radial current associates field-aligned current(FAC)and forms a three-dimensional current loop, respectively. Region 1 FAC and Region 2 FAC that are determined at low altitudes, manifest the superimposed, resultant effect of these current loops.During the substorm growth phase, ion plasma sheet that was inferred from the precipitating particles, consists of core part and cleft-like part. In the ion core part domain, enhanced westward azimuthal current loop associates Region 2-sense FAC and furthermore radial current loop causes Region 2 plus Region 1-sense FAC in pair. In the domain of ion cleft-like part, Region 1-sense FAC is associated with the convective flow vorticity in the near equatorial magnetotail. Whereas, in the expansion phase, disruption occurs rapidly in the preceding(growth phase), enhanced westward current and the growth phase-ion core part trns into the explosive part. Region 1-sense FAC is associated with this current disruption and reversed-Region I sense FAC(and/or multiple current shetts)is also associated, pole-ward of and adjacent-to the disruption region. The ion core part shifts far equator-ward and associates Region 2-sense FAC, and c upled Region 2 plus Region 1 FAC there.

近赤道磁层(L--4-9 R_E)中流动的电流由两个基本要素组成：方位电流和径向电流。方位流绕地球向西流动。径向流在深夜至午夜前流向地球，在午夜至清晨流向地球。磁层径向流的存在与极光纬度电离层佩德森流的逆流一致，投影在磁层赤道平面上。方位角和径向流的不均匀性与场对准电流（FAC）相关联并形成分别为三维电流环。在低空确定的区域 1 FAC 和区域 2 FAC 体现了这些电流环路的叠加综合效应。在亚暴生长阶段，从沉淀粒子推断出的离子等离子体片由核心部分和裂隙部分组成。在离子核心部分域中，增强的西向方位角电流环路与区域2-感测FAC相关联，此外径向电流环路导致区域2加区域1-感测FAC成对。在离子裂隙部分区域，区域1-sense FAC与近赤道磁尾的对流涡度相关。而在膨胀阶段，前期（生长阶段）破坏迅速，西向流增强，生长阶段离子核心部分转变为爆炸部分。区域 1 感测 FAC 与该电流中断相关，并且反向区域 I 感测 FAC（和/或多个电流片）也与中断区域的极点方向且邻近中断区域相关联。离子核心部分向赤道方向移动很远，并与区域 2 感测 FAC 以及耦合的区域 2 和区域 1 FAC 相关联。