We utilize 17 years of combined Van Allen Probes and Arase data to statistically analyze the response of the inner magnetosphere to the orientation of the interplanetary magnetic field (IMF) B_y component. Past studies have demonstrated that the IMF B_y component introduces a similarly oriented B_y component into the magnetosphere. However, these studies have tended to focus on field lines in the magnetotail only reaching as close to the Earth as the geosynchronous orbit. By exploiting data from these inner magnetospheric spacecraft, we have been able to investigate the response at radial distances of <7R_E. When subtracting the background magnetic field values, provided by the T01 and IGRF magnetic field models, we find that the IMF B_y component does affect the configuration of the magnetic field lines in the inner magnetosphere. This control is observed throughout the inner magnetosphere, across both hemispheres, all radial distances, and all magnetic local time sectors. The ratio of IMF B_y to the observed B_y residual, also known as the “penetration efficiency,” is found to be ∼0.33. The IMF B_z component is found to increase, or inhibit, this control depending upon its orientation.

中文翻译：

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磁层对星际磁场的内磁层响应：Van Allen探针和频变观测

我们利用Van Allen探针和Arase数据的17年组合来统计分析内部磁层对行星际磁场（IMF）B _y方向的响应。过去的研究表明，IMF B _y分量将类似取向的B _y分量引入磁层。但是，这些研究倾向于集中在磁尾中的磁力线上，磁力线仅到达地球与地球同步轨道一样近的位置。通过利用来自这些内部磁层航天器的数据，我们已经能够研究径向距离<7 R _E时的响应。当减去由T01和IGRF磁场模型提供的背景磁场值时，我们发现IMF B _y分量确实会影响内部磁层中磁力线的配置。在整个内部磁层，两个半球，所有径向距离和所有磁局部时区都可以观察到这种控制。发现IMF B _y与观察到的B _y残留之比，也称为“穿透效率”，约为0.33。发现IMF B _z分量取决于其方向来增加或抑制此控制。