[P-EM12] Space Weather, Space Climate, and VarSITI

[PEM12-P06] Comparison of Magnetospheric Magnetic Field Variations at Quasi-Zenith Orbit Based on Michibiki Observation and REPPU Global MHD Simulation

*久保田 康文¹、長妻 努¹、中溝 葵¹、坂口 歌織¹、田 光江¹、松本 晴久²、田中 高史³ (1.情報通信研究機構、2.宇宙航空研究開発機構、3.九州大学)

キーワード：グローバル磁気圏シミュレーション、表面帯電、磁場

We compare MHD simulation results with observations from Michibiki satellite, which is on the quasi-zenith orbit (QZO), for risk estimation of surface charging. The surface charging results from plasma injection related to substorm. We simulated some charging events and compared the magnetic field variation causing the plasma injection. However, magnetic field variations of simulation results tend to deviate from observations on QZO in disturbed geomagnetic condition. We consider that the deviation during disturbed geomagnetic condition is due to ring current enhancement in inner magnetosphere. In order to produce the magnetic field variation due to ring current, we added inner pressure model to MHD simulation, which produces ring current by artificially increasing pressure in inner magnetosphere. Then we investigated the magnetic field variation causing the plasma injection. As a result, we found that the magnetic field variation causing plasma injection is reproduced in simulation when we add the inner pressure model to MHD simulation. This result suggests that the change of magnetic field due to ring current in inner magnetosphere affects the magnetic field variation of the plasma injection caused by nightside reconnection.