Study on the inner magnetosphere based on comprehensive observation of plasma waves

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04056
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Kanazawa University
• Principal Investigator: Kasahara Yoshiya 金沢大学, 総合メディア基盤センター, 教授 (50243051)
• Co-Investigator(Kenkyū-buntansha): 笠羽 康正 東北大学, 理学研究科, 教授 (10295529)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 宇宙プラズマ / プラズマ波動 / 地球磁気圏・電離圏 / 計測工学 / 超高層物理学 / 自然現象観測・予測

Outline of Final Research Achievements

We established an intelligent measurement system for the plasma wave experiment (PWE) on board the Arase satellite. We demonstrated that electric and magnetic fields are precisely derived after appropriate calibration. We also established a data selection procedure to capture important waveform data which are closely related to the wave-particle interaction in the inner magnetosphere.
We successfully applied direction finding analysis to various kinds of plasma waves in order to quantitatively evaluate the generation and propagation mechanism of the waves. We also performed collaborative observations with ground-based networks as well as the other satellites such as Van Allen Probes, and succeeded in identifying the one-to-one relationship between chorus waves and pulsating auroras and the plasma waves propagating from the same wave source.

Free Research Field

電波情報工学

Academic Significance and Societal Importance of the Research Achievements

地球内部磁気圏の放射線帯は、数Hz～十数kHz帯にわたるプラズマ波群と、eV～MeV帯にわたる荷電粒子の相互作用によってダイナミックに生成・消滅を繰り返し、宇宙飛行士の被ばく、人工衛星の故障、降下電子による電離層擾乱（無線通信やGPS信号への影響）等、人類の活動に多大な影響を及ぼす。
当該研究は、あらせ衛星搭載のプラズマ波動観測器（PWE）を用いて、これらの物理機構に深く関わるプラズマ波を選択的に選んで精密測定する観測技術を確立した点、地上観測網や他衛星との同時観測によって、波動の励起源や伝搬通路をグローバルにとらえる観測に成功した点で、学術的に大変重要である。