[P-EM35_2PM1] プラズマ宇宙：シミュレーション技法，データ解析・可視化

[PEM35-03] 有限体積マルチモーメント移流法を用いた電磁ブラソフシミュレーション

*簑島 敬¹、松本 洋介²、天野 孝伸³ (1.海洋研究開発機構　地球内部ダイナミクス領域、2.千葉大学大学院理学研究科、3.東京大学 地球惑星科学専攻)

キーワード：移流方程式, ブラソフシミュレーション, 磁気リコネクション

The Vlasov simulation, which directly discretizes the Vlasov equation on grid points in phase space, has been proposed as an alternative method to the common Particle-In-Cell simulation, to improve the accuracy of kinetic plasma simulations. Although the electrostatic Vlasov simulations have been successfully carried out thus far, the electromagnetic Vlasov simulation of magnetized plasma is still limited, owing to numerical difficulty in solving the distribution function in velocity space.To overcome the difficulty, we develop a new numerical scheme, specifically designed to solve the Vlasov equation in magnetized plasma. The scheme advances multiple piecewise moments of a physical profile based on their governing equations, to preserve the profile with high accuracy. The scheme allows us to perform a long-time calculation of the distribution function of magnetized plasma with small numerical diffusion.In this talk, we first present the scheme and its performance. Then, we report the application of the scheme to two-dimensional (2D3V) electromagnetic Vlasov simulations. Long-time simulations of the linear wave propagation in magnetized plasma are conducted with quite small numerical errors. We also conduct the simulation of collisionless magnetic reconnection. The simulation resolves macroscopic structure without numerical noise, and is in good agreement with previous studies. Furthermore, the simulation resolves microscopic structure of the non-Maxwellian plasma velocity distribution around the reconnection site, e.g., acceleration by the reconnection electric field at the X-point, high energy beams around the boundary layer, and heating by the magnetic compression at the downstream. Since the simulations have been successfully carried out with the grid size much larger than the Debye length, the Vlasov simulation is a powerful technique to treat global-scale kinetic plasma phenomena.