講演情報
[PEM13-P02]Geomagnetic N+/O+ variation in the Ring Current Observed by the Arase (ERG) Satellite
*津田 洸一郎1、横田 勝一郎1、笠原 慧2、桂華 邦裕3、堀 智昭4、三好 由純4、篠原 育5、寺田 健太郎1 (1.大阪大学院理学研究科宇宙地球科学専攻、2.東京大学、3.東京大学大学院理学系研究科地球惑星科学専攻、4.名古屋大学宇宙地球環境研究所、5.宇宙航空研究開発機構/宇宙科学研究所)
キーワード：
Arase (ERG) 衛星、イオン流出、電離圏、窒素イオン
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.
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.