[P-EM17] 宇宙プラズマ理論・シミュレーション

[PEM17-04] Gyrokinetic simulation of drift wave instabilities and particle transport in a ring dipole configuration

坂野 純哉¹、*渡邉 智彦¹、前山 伸也¹ (1.名古屋大学大学院理学研究科)

キーワード：プラズマ、ドリフト波、双極子磁場

Plasma experiments using a ring dipole configuration have been conducted to explore plasma dynamics in a high beta regime, where the basic concept originates from the idea of energetic particle confinement in the radiation belts of the Earth and the Jupiter. The RT-1 experiment at University of Tokyo has demonstrated the inward particle transport toward the plasma core region with higher electron density and temperature.

To understand the transport mechanism in the ring dipole configuration, we have extended the gyrokinetic simulation code, GKV, and investigated linear stability properties of the electron temperature gradient (ETG) mode and the trapped electron mode (TEM) and their nonlinear evolutions leading to drift wave turbulence. We have identified the ETG instability in case with high electron temperature gradient, and the TEM instability with double peaks in the wavenumber spectra of the linear growth rates. The TEM excited in a high wavenumber regime is related to magnetic drift motions of circulating electrons, and not found in the conventional toroidal confinement. We have also revealed that the TEM in a low wavenumber region can drive the inward particle transport, and may lead to self-organization of plasma confinement. The present result provides ones a useful tool to investigate the plasma dynamics in the radiation belts of magnetized planets.