An Improved Method for Coupling Hydrodynamics with Astrophysical Reaction Networks

TL;DR

This paper introduces a simplified spectral deferred corrections (SDC) method for coupling hydrodynamics with nuclear reaction networks, improving accuracy and reducing computational costs in astrophysical simulations.

Contribution

The authors develop a simplified SDC approach for better coupling of hydrodynamics and reactions, which is easier to implement and more efficient than previous methods.

Findings

Improved coupling accuracy over traditional operator splitting.

Reduced computational expense in astrophysical simulations.

Effective application to double detonation problems.

Abstract

Reacting astrophysical flows can be challenging to model because of the difficulty in accurately coupling hydrodynamics and reactions. This can be particularly acute during explosive burning or at high temperatures where nuclear statistical equilibrium is established. We develop a new approach based on the ideas of spectral deferred corrections (SDC) coupling of explicit hydrodynamics and stiff reaction sources as an alternative to operator splitting that is simpler than the more comprehensive SDC approach we demonstrated previously. We apply the new method to a double detonation problem with a moderately-sized astrophysical nuclear reaction network and explore the timestep size and reaction network tolerances to show that the simplified-SDC approach provides improved coupling with decreased computational expense compared to traditional Strang operator splitting. This is all done in the framework of the Castro hydrodynamics code, and all algorithm implementations are freely available.