Quantifying Advantages of a Moving Mesh in Nuclear Hydrodynamics

TL;DR

This paper demonstrates that using a moving mesh technique in nuclear hydrodynamics simulations significantly reduces numerical diffusion in modeling astrophysical explosions, improving accuracy in simulating flame fronts and thermonuclear processes.

Contribution

The study applies and tests a moving mesh method in nuclear hydrodynamics, showing its advantages over fixed meshes in astrophysical explosion simulations.

Findings

Moving mesh reduces numerical diffusion in flame front simulations.

Moving mesh improves accuracy in advecting and deflagrating problems.

Semi-analytical solutions provide useful benchmarks for testing.

Abstract

Many astrophysical explosions, such as type Ia supernovae, classical novae, and X-ray bursts, are dominated by thermonuclear runaway. To model these processes accurately, one must evolve nuclear reactions concurrently with hydrodynamics. We present an application of the moving mesh technique to this field of computation with the aim of explicitly testing the advantages of the method against the fixed mesh case. By way of traditional Strang splitting, our work couples a 13 isotope nuclear reaction network to a 1D moving mesh, Cartesian geometry hydrodynamics code. We explore three reacting problems: an acoustic pulse, a burning shock, and an advecting deflagration. Additionally using the shock jump conditions, we semi-analytically solve the burning shock problem under the assumption of quick, complete burning with the hope of establishing a useful and easy to set-up test problem. Strong moving mesh advantages are found in advecting, deflagrating flame fronts, where the technique dramatically reduces numerical diffusion that would otherwise lead to very fast artificial deflagration.