日本地球惑星科学連合2014年大会

講演情報

ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM30_30PO1] プラズマ宇宙:乱流,輸送,非線形現象

2014年4月30日(水) 18:15 〜 19:30 5階ポスター会場 (5F)

コンビーナ:*松清 修一(九州大学大学院総合理工学研究院流体環境理工学部門)、中村 匡(福井県立大学)

18:15 〜 19:30

[PEM30-P02_30] ケルビン―ヘルムホルツ不安定性の非線形発展に対するイオンジャイロ運動の効果

*上野 悟志1梅田 隆行1中村 琢磨2町田 忍1 (1.名古屋大学太陽地球環境研究所、2.ロスアラモス国立研究所)

キーワード:the Kelvin-Helmholtz instability, Vlasov simulation, space plasma, nonlinear processes, secondary instabilities

Nonlinear evolution of the Kelvin-Helmholtz instability (KHI) at a transverse velocity shear layer in an inhomogeneous space plasma is investigated by means of a four-dimensional (two spatial and two velocity dimensions) electromagnetic Vlasov simulation. When the rotation direction of the primary KH vortex and the direction of ion gyro motion are same, there exists a strong ion cyclotron damping. In this case, spatial inhomogeneity inside the primary KH vortex is smoothed and the secondary Rayleigh-Taylor instability is suppressed. The ion gyro motion also suppresses the formation of secondary vortices in the spatial scale smaller than the ion gyro radius, when the rotation direction of the vortex and the direction of ion gyro motion are same. As a result, the secondary instabilities take place at different locations in the primary KH vortex, where the rotation direction of the secondary vortex and the direction of ion gyro motion are opposite. These results indicate that secondary instabilities occurring in the nonlinear stage of the primary KHI at the Earth's magnetospheric boundaries might show dawn-dusk asymmetries.