Termination of the MRI via parasitic instabilities in core-collapse supernovae: influence of numerical methods

TL;DR

This study investigates how numerical methods and grid resolution affect the termination of the MRI by parasitic instabilities in core-collapse supernova simulations, highlighting the importance of high-order schemes for convergence.

Contribution

It demonstrates that MRI termination by Kelvin-Helmholtz instabilities is consistent across numerical schemes and emphasizes the role of high-order methods for accurate, convergent results.

Findings

MRI termination caused by Kelvin-Helmholtz instabilities

High-order reconstruction methods enable numerical convergence

Qualitative results are scheme-independent

Abstract

We study the influence of numerical methods and grid resolution on the termination of the magnetorotational instability (MRI) by means of parasitic instabilities in three-dimensional shearing-disc simulations reproducing typical conditions found in core-collapse supernovae. Whether or not the MRI is able to amplify weak magnetic fields in this context strongly depends, among other factors, on the amplitude at which its growth terminates. The qualitative results of our study do not depend on the numerical scheme. In all our models, MRI termination is caused by Kelvin-Helmholtz instabilities, consistent with theoretical predictions. Quantitatively, however, there are differences, but numerical convergence can be achieved even at relatively low grid resolutions if high-order reconstruction methods are used.