Investigation of creation and transport mechanisms of energetic ions in deep inner magnetosphere and their dependence on ion species

2015 Fiscal Year Final Research Report

• Project/Area Number: 25287127
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Kyoto University
• Principal Investigator: Nose Masahito 京都大学, 理学(系)研究科(研究院), 助教 (90333559)
• Co-Investigator(Kenkyū-buntansha): KEIKA Kunihiro 名古屋大学, 宇宙地球環境研究所, 特任助教 (10719454) ; MIYASHITA Yukinaga 名古屋大学, 宇宙地球環境研究所, 特任助教 (20435811) ; NOMURA Reiko 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 宇宙航空プロジェクト研究員 (30637690) ; NAKANO Shinya 統計数理研究所, モデリング研究系, 助教 (40378576) ; OBANA Yuki 大阪電気通信大学, 工学部, 講師 (50398096) ; SHOJI Masafumi 名古屋大学, 宇宙地球環境研究所, 特任助教 (80722082)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: リングカレント / イオン組成 / 磁気嵐 / サブストーム / 酸素イオントーラス / 内部磁気圏

Outline of Final Research Achievements

The inner magnetosphere, that is, the near-Earth space where the weather satellite "Himawari" and the GPS satellites are flying, is filled with plasma consisting of charged particles. The dominant component of plasma in the inner magnetosphere is proton during ordinary times, whereas it becomes O+ ion once geomagnetic storms occur. In this study, we investigated the cause of the ion composition change, using data obtained by scientific satellites surveying the inner magnetosphere. It was found that O+ ions are directly flowing into the inner magnetosphere and they are accelerated locally and selectively by electromagnetic field disturbances accompanying with magnetic field dipolarization.

Free Research Field

磁気圏物理学