PANGU I：基于帕特农的固定时空广义相对论磁流体动力学框架
PANGU I: A Parthenon-Based Framework for Fixed-Spacetime GRMHD
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中文总结 AI 辅助
PANGU是一个模块化统一框架，集成共享求解器与灵活几何接口，其固定时空GRMHD组件经验证在多个区域达到二阶精度，并与现有代码结果一致。
中文摘要 AI 辅助
现有的广义相对论磁流体动力学（GRMHD）代码提供了互补的能力，但这些能力分散在不同的框架中。为了统一这些能力，我们引入了PANGU——统一框架中基于帕特农的天体物理数值相对论与GRMHD——一个模块化的计算框架，它在单一架构内集成了跨物理区域的共享求解器、灵活的时空几何以及可扩展的计算基础设施。在本系列的第一篇论文中，我们展示并验证了PANGU的固定时空GRMHD组件。共享求解器结合了有限体积Godunov方法与约束输运，适用于均匀和块结构、静态细化的网格，并涵盖牛顿、狭义相对论和广义相对论区域中的流体动力学和磁流体动力学。PANGU提供了一个灵活的几何接口，支持坐标选择以及即时或预计算的指定静态时空评估，此处以Kerr时空中的笛卡尔Kerr-Schild和修正Kerr-Schild坐标进行了演示；其他组件可以在不重构核心求解器的情况下纳入。验证涵盖了均匀和静态细化网格上的所有三个区域：平滑的牛顿和狭义相对论问题在解析解上达到二阶精度，刻意匹配的双精度轨迹与AthenaK在舍入误差范围内一致；在固定时空GRMHD中，静态解析解保持到二阶精度，湍流吸积再现了与BHAC相同的流动和通量尺度。这些结果共同为更广泛的PANGU框架奠定了固定时空物质扇区的基础。数值相对论和耦合动态时空GRMHD能力将在后续工作中展示。
英文摘要
Existing general-relativistic magnetohydrodynamics (GRMHD) codes offer complementary capabilities, but these capabilities remain distributed across different frameworks. To unify them, we introduce PANGU--Parthenon-Based Astrophysics for Numerical Relativity and GRMHD in a Unified Framework--a modular computational framework that integrates a shared solver across physical regimes, flexible spacetime geometry, and extensible computational infrastructure within a single architecture. In the first paper of this series, we present and validate the fixed-spacetime GRMHD component of PANGU. The shared solver combines finite-volume Godunov methods with constrained transport on uniform and block-structured, statically refined meshes, and covers hydrodynamics and magnetohydrodynamics in Newtonian, special-relativistic, and general-relativistic regimes. PANGU provides a flexible geometry interface supporting coordinate selection and either on-the-fly or precomputed evaluation of prescribed stationary spacetimes, demonstrated here in Kerr spacetime with Cartesian Kerr-Schild and modified Kerr-Schild coordinates; additional components can be incorporated without restructuring the core solver. Verification covers all three regimes on uniform and statically refined meshes: smooth Newtonian and special-relativistic problems approach second order against their analytic solutions, with deliberately matched double-precision trajectories agreeing with AthenaK to roundoff; in fixed-spacetime GRMHD, the stationary analytic solutions are preserved to second order, and the turbulent accretion reproduces the same flow and flux scales as BHAC. Together, these results establish the fixed-spacetime matter-sector foundation for the broader PANGU framework. Numerical-relativity and coupled dynamical-spacetime GRMHD capabilities will be presented in subsequent work.
发表机构
- School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）
- School of Physics, Peking University（北京大学物理学院）
- Key Laboratory of Multiscale Spin Physics, Ministry of Education（教育部多尺度自旋物理重点实验室）
- School of Physical Science and Technology, Ningbo University（宁波大学物理科学与技术学院）
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