紀要論文

磁気圏における運動論的アルフベン波の駆動するフィードバック不安定性に関するシミュレーション研究

SIMULATION STUDY ON FEEDBACK INSTABILITY DRIVEN BY KINETIC ALFVEN WAVE IN THE MAGNETOSPHERE

jpn

24368083

https://doi.org/10.15002/00025344

法政大学大学院理工学研究科

法政大学大学院紀要. 理工学研究科編

63

1

6

2022-03-24

Version of Record

ヘッダー部分に誤記 ; (誤) 法政大学大学院紀要理工学・工学研究科編 (正) 法政大学大学院紀要理工学研究科編

The feedback instability occurs in the interaction of the magnetospheric and ionospheric plasma through the kinetic Alfvén waves and is a theoretical model explaining spontaneous development of the quiet aurora. In this study, we perform a linear stability analysis and a nonlinear simulation of the feedback instability adopting a gyrofluid model to the magnetosphere. Using the gyrofluid model makes it possible to properly discuss kinetic effects in the magnetosphere. In the linear stability analysis, we analyze a finite Larmor radius effect on the feedback instability. It is found that the finite Larmor radius effect has destabilizing effects for the feedback instability and forms an unstable region with a strange shape in the wave number space perpendicular to the magnetic field. In the nonlinear simulation, we perform a spatiotemporal analysis and an energy transfer analysis on nonlinear evolution of the feedback instability. It is found that the spatiotemporal structure of perturbation has spatial anisotropy in directions parallel and perpendicular to a wave propagation direction. It is also found that electromagnetic nonlinearity is important in the nonlinear evolution of the feedback instability.

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