Japan Geoscience Union Meeting 2015

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International Session (Oral)

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

[P-EM09] Dynamics in magnetosphere and ionosphere

Thu. May 28, 2015 11:00 AM - 11:45 AM 302 (3F)

Convener:*Shin'ya Nakano(The Institute of Statistical Mathematics), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Hiroshi Hasegawa(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Yoshimasa Tanaka(National Institute of Polar Research), Tomoaki Hori(Nagoya University Solar Terrestrial Environment Laboratory Geospace Research Center), Chair:Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University)

11:15 AM - 11:30 AM

[PEM09-23] Non-active flow reversals in magnetotail

*Iku SHINOHARA1, Tsugunobu NAGAI2, Masaki FUJIMOTO1 (1.Japan Aerospace Exploration Agency / Institute of Space and Astronautical Science, 2.Tokyo Institute of Technology)

Keywords:magnetotail, flow reversal, magnetic reconnection

Geotail observation over 20 years in magnetotail provides us with about 200 rapid flow reversal events where tailward flow (< -500 km/s) turns to earthward flow (> +300 km/s) within 10 minutes. Nagai et al. (2013) proposed that Vey < -1000 km/s is an important criterion to select active X-lines. As a result, we get 30 active X-line crossing events. Active X-line events show electron acceleration during flow reversals and existence of ion-electron decoupling region. These features are consistent with the collisionless reconnection model demonstrated by recent full kinetic numerical simulations. In contrast, other 16 flow reversal events do not present any of them. No visible ion-electron decoupling is found in these non-Active flow reversal events. In this presentation, we will discuss physical meaning of the difference between active X-line and non-active flow reversal events.