Japan Geoscience Union Meeting 2015

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Poster

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

[P-EM28] Dynamics in magnetosphere and ionosphere

Wed. May 27, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

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

6:15 PM - 7:30 PM

[PEM28-P13] Geotail observations of dayside magnetopause reconnection II

*Shuichi ODAGIRI1, Kazufumi YOSHIDA1, Tsugunobu NAGAI2 (1.Earth and Planetary Sciences, Titech, 2.Tokyo Institute Of Technology)

Keywords:magnetosphere, magnetic reconnection

Plasma velocity distributions perpendicular to the magnetic field are generally isotropic by Larmor motion of ions and electrons. In actuality, isotropic velocity distributions are observed by Geotail. However, anisotropic ion velocity distributions were observed in the magnetosheath nearby the magnetopause when Geotail crossed the dayside magnetopause and observed ion flow jets by magnetic reconnection. The Geotail data of ion Energy-Time spectrogram on July 6, 2013 indicate anisotropic velocity distributions of ions energies higher than 20 keV at 0330 UT. The Geotail orbit is from magnetosheath through the magnetopause to the magnetosphere. The spacecraft GSM coordinates at the time of anisotropic ion velocity distribution observation are (9.8, 3.0, -0.2)RE. This Geotail position is in the magnetosheath nearby the magnetopause. Ion energies are about 1 keV in the distant magnetosheath from the magnetopause. There are no ions with energies higher than 10 keV in the magnetosheath. There are ions with energies higher than 20 keV in magnetosphere. Thus, these ions are considered to go out toward the magnetosheath from the magnetosphere. We explain anisotropic ion velocity distributions by reconnecting magnetic field geometry.