The RAGE radiation-hydrodynamic code

TL;DR

The paper introduces RAGE, a radiation-hydrodynamics code with advanced algorithms and validation, capable of efficient, robust simulations of radiation and hydrodynamics interactions.

Contribution

It presents a new radiation-hydrodynamics code with improved algorithms for hydrodynamics and radiation transport, including a novel approach to radiation-material coupling.

Findings

Enhanced robustness of hydrodynamic advection algorithms.

Convergent nonlinear treatment of radiation-material coupling.

Validated performance through extensive verification and validation.

Abstract

We describe RAGE, the ``Radiation Adaptive Grid Eulerian'' radiation-hydrodynamics code, including its data structures, its parallelization strategy and performance, its hydrodynamic algorithm(s), its (gray) radiation diffusion algorithm, and some of the considerable amount of verification and validation efforts. The hydrodynamics is a basic Godunov solver, to which we have made significant improvements to increase the advection algorithm's robustness and to converge stiffnesses in the equation of state. Similarly, the radiation transport is a basic gray diffusion, but our treatment of the radiation-material coupling, wherein we converge nonlinearities in a novel manner to allow larger timesteps and more robust behavior, can be applied to any multi-group transport algorithm.