AI 中文总结
本文针对10矩磁流体动力学提出一种能量一致有限差分格式，通过非线性滤波与能量转移保证总能量平衡，经多类测试验证其在宽等离子体beta范围的有效性，为无碰撞等离子体大规模模拟提供了新框架。
AI 中文摘要
压力各向异性和非对角压力应力在无碰撞/弱碰撞等离子体中普遍存在且发挥重要作用，常采用Chew-Goldberger-Low（CGL）磁流体动力学（MHD）模型，但该模型在压力各向异性或等离子体beta值较大时会失去双曲性，难以开发近似黎曼求解器。另一种方法是使用10矩MHD方程，但其本征模分析也较为困难，同样阻碍了低扩散黎曼求解器的开发。本文提出一种适用于10矩MHD的新型能量一致有限差分格式，可在宽范围等离子体beta值下运行；该格式采用传统MHD的能量一致有限差分方法扩展10矩MHD模型，对压力张量的6个独立分量均应用非线性滤波，并在能量均分假设下，将滤波耗散的动能和磁能明确转移至对角压力分量，以保持总能量平衡的一致性。通过7个测试问题对该格式进行验证，涵盖各向同性极限、陀螺ropic极限以及无各向同性化/陀螺ropic化的情况，结果表明该格式具有预期的空间收敛性和总能量行为，可再现线性增长率，且产生的压力张量结构在定性上与理论预期及以往模拟结果一致，覆盖等离子体beta值从10^-10到10^10的范围。该格式为宽范围等离子体beta regime下的无碰撞等离子体大规模模拟提供了有前景的框架，并为太阳风湍流、等离子体团介导重联等应用开辟了路径。
英文摘要
Pressure anisotropy and off-diagonal pressure stresses are ubiquitous and play important roles in collisionless/weakly collisional plasmas. The Chew-Goldberger-Low (CGL) MHD model is often used; however, it can lose hyperbolicity when the pressure anisotropy or plasma beta becomes large, making it hard to develop approximate Riemann solvers. An alternative approach is to use the 10-moment MHD equations, but their eigenmode analysis is also difficult, which similarly hinders the development of less-diffusive Riemann solvers. This paper presents a new energy-consistent finite difference scheme for 10-moment MHD designed to operate over a broad range of plasma beta. The proposed scheme extends the 10-moment MHD model using the energy-consistent finite-difference approach developed for conventional MHD. Nonlinear filtering is applied to all six independent components of the pressure tensor, and the kinetic and magnetic energies dissipated by the filtering are explicitly transferred to the diagonal pressure components under an equipartition assumption to maintain consistency with the total energy balance. The proposed scheme is validated against seven test problems in the isotropic limit, the gyrotropic limit, and without isotropization/gyrotropization. The results demonstrate the expected spatial convergence and total energy behavior, reproduce the linear growth rate, and yield pressure tensor structures qualitatively consistent with theoretical expectations and previous simulations, spanning plasma beta values from $10^{-10}$ to $10^{10}$. The proposed scheme provides a promising framework for large-scale simulations of collisionless plasmas across widely separated plasma beta regimes and opens a path toward applications such as solar wind turbulence and plasmoid-mediated reconnection.
Comments26 pages, 16 figures, submitted to Journal of Computational Physics
