发表机构
Hong Kong University of Science and Technology; Xi’an Jiaotong University（香港科技大学; 西安交通大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出极谐统一气体动理学格式（PH-UGKS），统一求解磁化离子从回旋动理学到霍尔-佩德森漂移扩散的输运，通过精确碰撞-旋转积分和渐近保持实现跨尺度高效模拟。
AI 中文摘要
弱电离等离子体中的磁化离子输运随碰撞性和磁化强度的变化，范围从回旋角依赖的动理学到霍尔-佩德森漂移扩散。我们针对均匀磁场中的离子Vlasov-BGK方程，发展了一种极谐统一气体动理学格式（PH-UGKS）。该格式通过将守恒密度更新与非平衡分量的指数演化耦合，来演化完整的离子分布函数。在回旋角傅里叶空间中，精确的碰撞-旋转积分与时间平均的动理学通量相结合，该通量包含空间输运和电场加速，并辅以对密度通量的紧凑霍尔-佩德森修正。该格式守恒离子数，分析确立了二阶时间一致性和在固定磁化强度下对霍尔-佩德森密度极限的渐近保持。数值测试再现了离子伯恩斯坦色散和Dory-Guest-Harris增长率，并解析了碰撞频率与回旋频率之比变化时回旋谐波谱的变化。驱动的离子通量响应与独立的特征-沃尔泰拉参考一致，包括偏离瞬时霍尔-佩德森关系的有限频率偏差。在碰撞测试中，使用远大于碰撞时间和回旋周期的时间步长即可获得准确响应。固定分辨率密度测试确认了收敛到相应的霍尔-佩德森离散化。因此，同一动理学公式将动理学响应与宏观输运联系起来，而无需切换到流体求解器或对微观时间尺度进行子循环。
英文摘要
Magnetized ion transport in weakly ionized plasmas ranges from gyroangle-dependent kinetics to Hall-Pedersen drift-diffusion as collisionality and magnetization vary. We develop a polar-harmonic unified gas-kinetic scheme (PH-UGKS) for the ion Vlasov-BGK equation in a uniform magnetic field. The scheme evolves the full ion distribution by coupling a conservative density update to exponential evolution of its nonequilibrium component. Exact collision-rotation integration in gyroangle Fourier space is combined with a time-averaged kinetic flux that incorporates spatial transport and electric acceleration, together with a compact Hall-Pedersen correction to the density flux. The scheme conserves ion number, and analysis establishes second-order temporal consistency and asymptotic preservation of the Hall-Pedersen density limit at fixed magnetization. Numerical tests reproduce ion Bernstein dispersion and Dory-Guest-Harris growth rates and resolve changes in the gyroharmonic spectrum as the collision-to-gyrofrequency ratio varies. The driven ion-flux response agrees with an independent characteristic-Volterra reference, including finite-frequency departures from the instantaneous Hall-Pedersen relation. In collisional tests, accurate responses are obtained with time steps far larger than both the collision time and the gyroperiod. Fixed-resolution density tests confirm convergence to the corresponding Hall-Pedersen discretization. The same kinetic formulation thus connects kinetic response and macroscopic transport without switching to a fluid solver or subcycling microscopic time scales.
