Crash: A Block-Adaptive-Mesh Code for Radiative Shock Hydrodynamics - Implementation and Verification

TL;DR

The paper introduces the CRASH code, a sophisticated adaptive mesh radiation hydrodynamics simulation tool capable of multi-material, multi-dimensional modeling with advanced physics modules, verified through comprehensive test problems.

Contribution

The paper presents the implementation of the CRASH code, extending the BATS-R-US framework with new radiation transfer, heat conduction, and multi-material capabilities for accurate shock hydrodynamics simulations.

Findings

Demonstrated accuracy through verification test problems

Achieved efficient multi-dimensional simulations

Extended BATS-R-US with radiation and heat conduction modules

Abstract

We describe the CRASH (Center for Radiative Shock Hydrodynamics) code, a block adaptive mesh code for multi-material radiation hydrodynamics. The implementation solves the radiation diffusion model with the gray or multigroup method and uses a flux limited diffusion approximation to recover the free-streaming limit. The electrons and ions are allowed to have different temperatures and we include a flux limited electron heat conduction. The radiation hydrodynamic equations are solved in the Eulerian frame by means of a conservative finite volume discretization in either one, two, or three-dimensional slab geometry or in two-dimensional cylindrical symmetry. An operator split method is used to solve these equations in three substeps: (1) solve the hydrodynamic equations with shock-capturing schemes, (2) a linear advection of the radiation in frequency-logarithm space, and (3) an implicit solve of the stiff radiation diffusion, heat conduction, and energy exchange. We present a suite of verification test problems to demonstrate the accuracy and performance of the algorithms. The CRASH code is an extension of the Block-Adaptive Tree Solarwind Roe Upwind Scheme (BATS-R-US) code with this new radiation transfer and heat conduction library and equation-of-state and multigroup opacity solvers. Both CRASH and BATS-R-US are part of the publicly available Space Weather Modeling Framework (SWMF).