[P-PS05] Mercury Science and Exploration

[PPS05-05] Solar wind-magnetosphere-surface coupling and planetary ion escape in Mercury’s magnetosphere

★Invited Papers

*Weijie Sun¹ (1.Space Sciences Laboratory, University of California, Berkeley)

キーワード：Mercury, flux transfer event, planetary ion escape, magnetic reconnection, magnetosphere

Mercury is the planet closest to the Sun, which possesses a global intrinsic magnetic field that interacts with the solar wind to form a small magnetosphere. Unlike other planets in the solar system, Mercury lacks a significant atmosphere; instead, it has a surface-bounded exosphere. The magnetopause of Mercury’s magnetosphere near the subsolar point is located approximately one thousand kilometers above the planet’s surface. The solar wind near Mercury’s orbit is the strongest among planetary magnetospheres, characterized by higher dynamic pressure and stronger interplanetary magnetic field (IMF) intensity. In this presentation, we show our studies of solar wind-magnetosphere-surface coupling and planetary ion escape in Mercury’s magnetosphere based on the analysis of measurements from the MESSENGER spacecraft. We start with the flux transfer event “showers” formed by multiple reconnection X-lines on the magnetopause. These FTE showers contain FTEs with high succession rates (about 10 FTEs per minute) and are a common feature on Mercury’s magnetopause. The FTE showers play a significant role in transporting magnetic and particle flux in Mercury’s magnetosphere. Additionally, we provide observational evidence of how magnetospheric dynamics influence the planetary ions in Mercury’s magnetosphere. Finally, we present our latest findings on the escape plume of planetary ions, i.e., Na⁺-group ions, in the solar wind and magnetosheath along with the planetary ion escape rates in the magnetosphere under different true anomaly angle intervals.