2023 Fiscal Year Final Research Report
Evaluation of the formation mechanism of planetary radiation belts by direct measurement of particle acceleration processes
| Project/Area Number |
18H03727
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Review Section |
Medium-sized Section 17:Earth and planetary science and related fields
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
Katoh Yuto 東北大学, 理学研究科, 教授 (60378982)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
笠原 慧 東京大学, 大学院理学系研究科(理学部), 准教授 (00550500)
|
|---|
| Project Period (FY) |
2018-04-01 – 2023-03-31
|
| Keywords | 宇宙プラズマ・プラズマ波動 / 地球惑星磁気圏 / 太陽地球システム・宇宙天気 / オーロラ・磁気嵐 |
|---|
| Outline of Final Research Achievements |
To reveal the particle acceleration process by wave-particle interactions in planetary magnetospheres, we carried out (1) spacecraft data analysis, (2) numerical simulations, and (3) development of the method for the wave-particle interaction analyzer (WPIA). By a series of self-consistent simulations, we revealed the conditions required for efficient particle acceleration by nonlinear effects in the generation process of whistler-mode chorus emissions. We also revealed the process of 'anomalous trapping', in which almost all of the low pitch angle electrons are trapped by coherent whistler-mode waves and scattered away from the loss cone. We developed a calibration method that accurately satisfies the continuity of the wave phase of the waveform measured by instruments onboard a spacecraft, which is crucial for the WPIA. We applied the WPIA to the MMS spacecraft measurements of whistler-mode waves and keV electrons to detect the energy transfer through wave-particle interaction.
|
| Free Research Field |
宇宙空間プラズマ物理学
|
| Academic Significance and Societal Importance of the Research Achievements |
放射線帯は地球をはじめとする磁化惑星の周辺に共通して存在しており、その生成過程の理解は普遍的な粒子加速過程の解明につながる。本研究ではプラズマ波動との非線形波動粒子相互作用により高効率な電子加速過程を生じうること、その直接観測に本研究が提案する手法・Wave-Particle Interaction Analyzer (WPIA)が有効であることをそれぞれ示した。本研究で確立した波動粒子相互作用を直接計測するための一連の解析の方法論は、科学衛星による観測結果の解析への応用に加えて、プラズマ科学など波動粒子相互作用が関わる分野への展開も期待される。
|
