JpGU-AGU Joint Meeting 2020

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

[P-EM13] Dynamics of Magnetosphere and Ionosphere

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), Yuka Sato(Nippon Institute of Technology)

[PEM13-P02] Geomagnetic N+/O+ variation in the Ring Current Observed by the Arase (ERG) Satellite

*Koichiro Tsuda1, Shoichiro Yokota1, Satoshi Kasahara2, Kunihiro Keika3, Tomoaki Hori4, Yoshizumi Miyoshi4, Iku Shinohara5, Kentaro Terada1 (1.Department of Earth and Space Science, Graduate School of Science, Osaka University, 2.The University of Tokyo, 3.Department of Earth and Planetary science, Guraduate School of Science, The University of Tokyo, 4.Institute for Space-Earth Environment Research, Nagoya University, 5.Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science)

Keywords:Arase (ERG) satellite, Ion outflow, Ionosphere, Nitrogen ion

O+ and N+ are important ring current ions in magnetic storms and they can be a tracers of ion outflows from the deep ionosphere. Much Many researches haves been devoted to the escape of O+, but N+ has not been studied much, possibly because its mass per charge ratio is similar to that of O+ and separating the two is difficult.
We investigated the statistical properties of O+ and N+ in the ring current based on ion composition measurements (~10-180keV/q) by medium-energy particle experiments-ion mass analyzer (MEP-i) on board the Arase (Exploration of energization and Radiation in Geospace, ERG) satellite. By applying a fitting function to the TOF spectrum, we can separated N+ and O+ in the data obtained during geomagnetic storm on 16 July 2017. From the results of fitting we obtained the ratio of N+/O+. As a result the ratio of N+/O+ during geomagnetic storm and during geomagnetic quiet times is found to be about 0.2~0.4 and <0.2 respectively. In this presentation we will discuss ion outflow from the deep ionosphere.