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动态时空中的相对论辐射磁流体力学:数值方法和试验

Relativistic Radiation Magnetohydrodynamics in Dynamical Spacetimes: Numerical Methods and Tests

Brian D. Farris, Tsz Ka Li, Yuk Tung Liu, Stuart L. Shapiro

摘要:

当前相对论天体物理学中的许多系统都需要了解在强弯曲动态时空中流动的磁化气体的辐射转移。这类系统包括包含中子星或白矮星的合并致密双星、合并黑洞周围的圆盘、核心坍缩超新星、超新星和伽马射线暴源。为了模拟这些现象,所有这些都涉及到广义相对论,辐射(光子和/或中微子),磁流体力学,我们已经开发了一个广义相对论代码能够在动态时空中发展MHD流体和辐射。我们的代码解决了耦合Einstein-Maxwell-MHD-辐射方程组在轴对称和全3+1维。我们通过积分BSSN方程来演化度量,并使用保守的高分辨率激波捕获方案来演化MHD和辐射矩方程。在本文中,我们实现了我们的计划,光学厚气体和灰体不透明度。我们的代码给出了准确的结果,在一套测试涉及辐射冲击和非线性波传播在闵可夫斯基时空。此外,为了测试我们的代码的能力,在强场动力学时空相对论辐射MHD方程的发展,我们研究了“热奥本海默-斯奈德崩溃”的黑洞,并找到很好的协议之间的解析解和数值解。

英文摘要:

Many systems of current interest in relativistic astrophysics require a knowledge of radiative transfer in a magnetized gas flowing in a strongly-curved, dynamical spacetime. Such systems include coalescing compact binaries containing neutron stars or white dwarfs, disks around merging black holes, core collapse supernovae, collapsars, and gamma-ray burst sources. To model these phenomena, all of which involve general relativity, radiation (photon and/or neutrino), and magnetohydrodynamics, we have developed a general relativistic code capable of evolving MHD fluids and radiation in dynamical spacetimes. Our code solves the coupled Einstein-Maxwell-MHD-Radiation system of equations both in axisymmetry and in full 3+1 dimensions. We evolve the metric by integrating the BSSN equations, and use a conservative, high-resolution shock-capturing scheme to evolve both the MHD and radiation moment equations. In this paper, we implement our scheme for optically thick gases and grey-body opacities. Our code gives accurate results in a suite of tests involving radiating shocks and nonlinear waves propagating in Minkowski spacetime. In addition, to test our code's ability to evolve the relativistic radiation-MHD equations in strong-field dynamical spacetimes, we study "thermal Oppenheimer-Snyder collapse" to a black hole, and find good agreement between analytic and numerical solutions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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