Study on the acceleration and loss of ring current ions using multiple spacecraft in the inner magnetosphere

2017 Fiscal Year Final Research Report

• Project/Area Number: 26800257
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Space and upper atmospheric physics
• Research Institution: The University of Tokyo (2016-2017); Nagoya University (2014-2015)
• Principal Investigator: Keika Kunihiro 東京大学, 大学院理学系研究科(理学部), 助教 (10719454)
• Research Collaborator: Lanzerotti Louis J. ニュージャージー工科大学, 特任教授 ; Spence Harlan ニューハンプシャー大学, 教授 ; KASAHARA Satoshi 東京大学, 大学院理学系研究科, 准教授
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: Inner magnetosphere / geomagnetic storms / ring current / Acceleration and loss / Outflow and transport

Outline of Final Research Achievements

This study investigated spatial and temporal variations of plasma pressure in the inner magnetosphere (inside of ~10 Earth radii), the inner part of the region where the Earth’s magnetic field dominates, using data from in-situ observations by several spacecraft. The results show that (1) the energy of plasma that make the dominant contribution to plasma pressure changes in time during a magnetic storm and that (2) oxygen ions of Earth’s atmospheric origin are transported to around the outer edge of the inner magnetosphere to contribute to an increase in plasma pressure. Result (1) indicates the importance of spatial and temporal changes in plasma characteristics in the magnetotail. Result (2) suggests a new picture of the dynamics (transport, acceleration, circulation, etc.) of ionized atmospheric oxygen ions in the magnetosphere.

Free Research Field

Magnetospheric plasma physics