Effects of Resistivity on Magnetized Core-Collapse Supernovae

TL;DR

This study investigates how turbulent resistivity influences the dynamics and explosion mechanisms of magnetized core-collapse supernovae through 2D resistive-MHD simulations, revealing that resistivity can both suppress and enhance explosions depending on initial conditions.

Contribution

It provides the first detailed analysis of resistivity effects on magnetic field amplification and explosion dynamics in magnetized supernovae using resistive-MHD simulations.

Findings

Resistivity attenuates explosions in strongly magnetized rotating cores.

Resistivity enhances explosion in very strongly magnetized non-rotating cores.

Resistivity reduces the aspect ratio of ejected matter in rotating models.

Abstract

We studied roles of a turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out 2D-resistive-MHD simulations. The three cases with different initial strengths of magnetic field and rotation are investigated; 1. strongly magnetized rotating core; 2.moderately magnetized rotating core; 3. very strongly magnetized non-rotating core. In each case, both an ideal-MHD model and resistive-MHD models are computed. As a result of computations, each model shows a matter eruption helped by a magnetic acceleration (and also by a centrifugal acceleration in the rotating cases). We found that a resistivity attenuates the explosion in case~1 and 2, while it enhances the explosion in case~3. We also found that in the rotating cases, main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of magnetic field and a winding of poloidal magnetic field-lines by differential rotation, which are somewhat dampened down with the presence of a resistivity. Although the magnetorotational instability seems to occur in the rotating models, it will play only a minor role in a magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matters, $> 2.5$, attained in a ideal-MHD model is reduced to some extent in a resistive model. These results indicate that a resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.