Japan Geoscience Union Meeting 2019

Presentation information

[E] Poster

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM11] Dynamics of Magnetosphere and Ionosphere

Wed. May 29, 2019 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Aoi Nakamizo(Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology), Mitsunori Ozaki(Faculty of Electrical and Computer Engineering, Institute of Science and Engineering, Kanazawa University), Akiko Fujimoto(Kyushu Institute of Technology), Tomoaki Hori(Institute for Space-Earth Environmental Research, Nagoya University)

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

*Masaki N Nishino1,2, Yoshifumi Saito2, Kazuo Shiokawa1, Masaki Fujimoto2 (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.JAXA/ISAS)

Keywords: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.