11:30 〜 11:45
[PEM10-09] Seasonal Effects on Modeling of Soft X-ray Imaging of the Earth's Magnetosphere Under Disturbed Solar Wind Conditions
Solar Wind Charge eXchange (SWCX), which occurs between highly charge-state heavy ions in the solar wind and neutral atoms in the exosphere, emits soft X-rays. This emission process is useful for visualizing the dayside magnetosphere and its response to solar wind variations. The SMILE and GEO-X missions have been proposed to provide soft X-ray images of the magnetosheath and cusps and will contribute to a better understanding of the dynamic response of the Earth's magnetosphere.
For this purpose, we have developed a global magnetohydrodynamic simulation model of the magnetosphere (Matsumoto and Miyoshi, 2022). The model can provide three-dimensional distributions of the soft X-ray intensity from the plasma parameters. Then line-of-sight integrations of the intensity distribution give a two-dimensional X-ray map as a virtual observation in the simulation domain. To examine simulations under more realistic conditions, we have introduced the tilt of the geomagnetic dipole moment with respect to the rotational axis. Using this new model, we examined the magnetospheric responses to various solar wind conditions. Under the normal solar wind, we found that the X-ray emission intensity at the maximum tilt (at solstice during northern summer) was about 1.5 times brighter than that without the tilt, and the brightness at the cusp is significantly north-south asymmetric. Secondly, we have examined the changes in the soft X-ray emission for a disturbed solar condition modeling coronal mass ejection (CME) events during the interaction with the magnetosphere. We found that when the interplanetary shock and the CME arrived at the Earth's magnetosphere, the emission was about 3 times brighter than that under normal solar wind. In this presentation, we report the status of the model development and discuss the effects on the intensity and distribution of 2D X-ray maps depending on the season and solar wind conditions.
For this purpose, we have developed a global magnetohydrodynamic simulation model of the magnetosphere (Matsumoto and Miyoshi, 2022). The model can provide three-dimensional distributions of the soft X-ray intensity from the plasma parameters. Then line-of-sight integrations of the intensity distribution give a two-dimensional X-ray map as a virtual observation in the simulation domain. To examine simulations under more realistic conditions, we have introduced the tilt of the geomagnetic dipole moment with respect to the rotational axis. Using this new model, we examined the magnetospheric responses to various solar wind conditions. Under the normal solar wind, we found that the X-ray emission intensity at the maximum tilt (at solstice during northern summer) was about 1.5 times brighter than that without the tilt, and the brightness at the cusp is significantly north-south asymmetric. Secondly, we have examined the changes in the soft X-ray emission for a disturbed solar condition modeling coronal mass ejection (CME) events during the interaction with the magnetosphere. We found that when the interplanetary shock and the CME arrived at the Earth's magnetosphere, the emission was about 3 times brighter than that under normal solar wind. In this presentation, we report the status of the model development and discuss the effects on the intensity and distribution of 2D X-ray maps depending on the season and solar wind conditions.