[PEM13-P22] Near-earth plasma environment and injection simulated by global magnetosphere model with precession of magnetic axis
キーワード：電離圏伝導度効果、プラズマインジェクション、グローバル磁気圏シミュレーション
The plasma distribution from the inner plasma sheet to the geosynchronous orbit is the important information not only as the plasma supply for the inner magnetosphere but also as the environment for artificial satellites. Besides, disturbances such as the plasma bubble intrusion and/or plasma injection associated with tail dynamics and substorms are superposed on the background population in that region.
Global MHD simulation is one of the powerful ways to complement observations and to know deductively what is going on in that region. However, there has been much room for improvement in our model toward the realistic simulation. In this paper, we report our recent model improvements and the performances. The improvement targeting on the magnetosphere-ionosphere coupling process is reported separately.
In order to accurately calculate the magnetic field configuration, we introduced the inclination of the magnetic axis (tilt). Besides, we introduce the precession between the magnetic axis and the rotation axis. Although the precession may appear to be less effective, it is considered to be effective because it alters the ionospheric conductance distribution, which largely modify the magnetospheric convection and dynamics (and therefore the plasma environment in the near-earth region) through the M-I coupling processes as shown by Nakamizo and Yoshikawa [2019]. Actually, background plasma distribution and intrusion from the plasma sheet are quite different between simulations with and without precession. We will show the results for equinoxes and solstices.
References:
Nakamizo, A., & Yoshikawa, A. (2019). Deformation of ionospheric potential pattern by ionospheric Hall polarization. Journal of Geophysical Research: Space Physics, 124, 7553– 7580. https://doi.org/10.1029/2018JA026013
Global MHD simulation is one of the powerful ways to complement observations and to know deductively what is going on in that region. However, there has been much room for improvement in our model toward the realistic simulation. In this paper, we report our recent model improvements and the performances. The improvement targeting on the magnetosphere-ionosphere coupling process is reported separately.
In order to accurately calculate the magnetic field configuration, we introduced the inclination of the magnetic axis (tilt). Besides, we introduce the precession between the magnetic axis and the rotation axis. Although the precession may appear to be less effective, it is considered to be effective because it alters the ionospheric conductance distribution, which largely modify the magnetospheric convection and dynamics (and therefore the plasma environment in the near-earth region) through the M-I coupling processes as shown by Nakamizo and Yoshikawa [2019]. Actually, background plasma distribution and intrusion from the plasma sheet are quite different between simulations with and without precession. We will show the results for equinoxes and solstices.
References:
Nakamizo, A., & Yoshikawa, A. (2019). Deformation of ionospheric potential pattern by ionospheric Hall polarization. Journal of Geophysical Research: Space Physics, 124, 7553– 7580. https://doi.org/10.1029/2018JA026013