发表机构
California Institute of Technology（加州理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出广义相对论19矩耗散磁流体动力学表述，推导非线性因果条件，开发高性能激波捕获格式，并验证于黑洞吸积等场景，捕获重联率等关键特征。
AI 中文摘要
我们提出了一种广义相对论（GR）19矩耗散磁流体动力学（MHD）的表述，能够处理所有一阶耗散项（黏性、热传导、电阻率和霍尔项），以及GR天体物理双流体等离子体中所有理想电子自由度（数密度、动量和能量）。我们推导了约束一阶19矩系统的必要且充分的非线性因果条件，以及强双曲性的必要和充分条件。为了数值评估该表述，我们开发了一种高性能可移植的高分辨率激波捕获格式，以求解这些方程。该格式将所有演化方程（包括耗散和电子部分）表示为通量散度形式，使我们能够模拟尺度相差多个数量级的系统，而无需在网格上处处解析动力学尺度。此外，我们使用隐式积分方法系统地跨越MHD区域中的动力学尺度，如回旋频率和等离子体频率。为使该格式像GRMHD代码一样稳健，我们构造了守恒态物理上可接受的必要且充分条件，并基于这些条件构建了一种新的物理性强制方案。作为精确验证比较，我们推导并求解了广义相对论中耗散双流体Bondi吸积的完整解。然后，我们针对黑洞吸积和磁层动力学的动力学粒子-网格模型的一系列结果验证了这些方程，证明我们的表述和格式能够正确捕获这些解对全局尺度反馈的主要特征，包括量级为$0.1$的无量纲重联率以及类似Braginskii的各向异性压力和热通量。
英文摘要
We present a formulation of general-relativistic (GR) 19-moment dissipative magnetohydrodynamics (MHD), capable of handling all first-order dissipative terms (viscosity, heat conductivity, resistivity and Hall terms), as well as all ideal electron degrees of freedom (number density, momentum and energy) in a GR astrophysical two-fluid plasma. We derive necessary and sufficient nonlinear causality conditions for the constrained first-order 19-moment system, as well as both necessary and sufficient conditions for strong hyperbolicity. To assess the formulation numerically, we develop a high-resolution shock-capturing scheme that solves these equations in a performance-portable fashion. The scheme expresses all evolution equations, including the dissipative and electron sectors, in flux-divergence form, allowing us to model systems with scales separated by orders of magnitude without resolving kinetic scales everywhere on the grid. In addition, we use implicit integration methods to systematically overstep kinetic scales in MHD regions, such as cyclotron and plasma frequencies. To make the scheme as robust as GRMHD codes, we construct necessary and sufficient conditions for a conserved state to be physically admissible, and based on these construct a new physicality-enforcement scheme. As an exact validation comparison, we formulate and derive a full solution to dissipative two-fluid Bondi accretion in general relativity. We then validate the equations against a series of results from kinetic particle-in-cell models of black hole accretion and magnetospheric dynamics, demonstrating that our formulation and scheme can correctly capture major features relevant for feedback on global scales of these solutions, including dimensionless reconnection rates of order $0.1$ and Braginskii-like anisotropic pressures and heat fluxes.
Comments82 pages,16 figures
