日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM11] Dynamics of Magnetosphere and Ionosphere

2019年5月29日(水) 13:45 〜 15:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:中溝 葵(情報通信研究機構 電磁波研究所)、尾崎 光紀(金沢大学理工研究域電子情報学系)、藤本 晶子(九州工業大学)、堀 智昭(名古屋大学宇宙地球環境研究所)

[PEM11-P02] Asymmetric deformation of the magnetosphere under low-density solar wind

*Masaki N Nishino1,2Yoshifumi Saito2Kazuo Shiokawa1Masaki Fujimoto2 (1.Institute for Space-Earth Environmental Research, Nagoya University、2.JAXA/ISAS)

キーワード:Low density solar wind, Magnetosphere, Plasma transport

The density of the solar wind around the Earth's magnetosphere sometimes decreases to only several percent of the usual value, and such density extrema results in a significant reduction of dynamic pressure and Alfvenic Mach number of the solar wind flow. While simple expansion of the Earth's magnetosphere by the low dynamic pressure was assumed in previous studies, a global-MHD simulation study predicted a remarkable dawn-dusk asymmetry of the magnetosphere in shape under low-density solar wind and Parker-spiral IMF configuration. Here we present evidence of asymmetric deformation of the magnetosphere under low-density solar wind and Parker-spiral IMF conditions, based on several events of GEOTAIL observations. As predicted by the global-MHD simulation, the magnetosphere on the dawnside expands much further than the magnetopause location of simple (symmetric) expansion, while no significant expansion is detected in the dusk tail flank. Fast ion beams detected at the flank magnetopause suggest that magnetic reconnection frequently occurs due to the low-beta environment of the magnetosheath.