Field‐Aligned Electron Density Distribution of the Inner Magnetosphere Inferred From Coordinated Observations of Arase and Van Allen Probes
Field‐Aligned Electron Density Distribution of the Inner Magnetosphere Inferred From Coordinated Observations of Arase and Van Allen Probes
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根据 Arase 和 Van Allen 探测器的协调观测推断出内磁层的场对准电子密度分布
DOI：
10.1029/2020ja029073
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
MacDowall Robert J
中科院分区：
文献类型：
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作者：
Obana Yuki;Miyashita Yukinaga;Maruyama Naomi;Shinbori Atsuki;Nose Masahito;Shoji Masafumi;Kumamoto Atsushi;Tsuchiya Fuminori;Matsuda Shoya;Matsuoka Ayako;Kasahara Yoshiya;Miyoshi Yoshizumi;Shinohara Iku;Kurth William S.;Smith Charles W.;MacDowall Robert J
辐射带风暴探测器（RBSP）和Arase卫星有不同的倾角，有时它们在同一条磁场线上同时在赤道附近和赤道外飞行。这种会合事件使我们有机会比较不同纬度的电子密度。在这项研究中，我们分析了Arase和RBSP在2017年9月7日风暴期间和之后的三次会合事件中观测到的等离子体波。卫星位置处的电子数密度是根据分别由Arase机载等离子体波实验的高频分析仪和RBSP机载波仪器获得的上混合共振发射的频率来估计的。在这三次会合事件中，卫星穿过了羽流、内槽（等离子体云主体和羽流之间电子密度低的狭窄区域）、电子密度可变的等离子体云和部分再填充的等离子体云。内槽和羽流的幂律指数m被推断为分别为4-7和100。这被解释为意味着槽是接近碰撞和羽流是相对接近扩散平衡。在密度变化的等离子体粗糙中，高密度区和低密度区的密度均为0。这个区域的低密度部分可能与内槽有不同的起源，因为不同的思想。对于风暴恢复阶段部分再填充的等离子体，幂律指数显示负值，这意味着赤道平面的密度高于高纬度。
The Radiation Belt Storm Probes (RBSP) and the Arase satellites have different inclinations and sometimes they fly both near the equator and off the equator on the same magnetic field line simultaneously. Such conjunction events give us opportunities to compare the electron density at different latitudes. In this study, we analyzed the plasma waves observed by Arase and RBSP during the three conjunction events during and after the September 7, 2017 storm. The electron number density at the satellite positions was estimated from frequencies of the Upper Hybrid Resonance emissions obtained by the High Frequency Analyzer of the Plasma Wave Experiment onboard the Arase and the Waves instrument onboard the RBSP, respectively. During the three conjunction events, the satellites passed through the plume, inner trough (the narrow region with low electron density between the main body of the plasmasphere and the plume), plasmatrough with variable electron density, and partially refilled plasmasphere. The power‐law indexmfor the inner trough and plume was inferred to be 4–7 and ∼0, respectively. This is interpreted to mean that the trough was close to collisionless and the plume was relatively near diffusive equilibrium. In the plasmatrough with the varying density, both the high‐density and low‐density regions hadm∼ 0. The low‐density portion of this region may have a different origin from the inner trough, because of the differentmindices. For the partially refilled plasmasphere in the storm recovery phase, the power‐law indexmshowed negative values, meaning that the density in the equatorial plane was higher than at higher latitudes.