Magnetohydrodynamic Turbulence Powered by Magnetorotational Instability in Nascent Proto-Neutron Stars

TL;DR

This study uses 3D simulations to show that magnetorotational instability induces turbulence around the neutrinosphere in proto-neutron stars, potentially influencing supernova explosions.

Contribution

It demonstrates that MRI-driven turbulence occurs in the neutrinosphere's stable layer, revealing a new mechanism affecting supernova dynamics.

Findings

MRI induces turbulence in the neutrinosphere's stable layer

Turbulence intensity increases with magnetic flux

MRI-driven turbulence may positively impact supernova explosions

Abstract

Magnetorotational instability (MRI) in a convectively-stable layer around the neutrinosphere is simulated by a three-dimensional model of supernova core. To resolve MRI-unstable modes, a thin layer approximation considering only the radial global stratification is adopted. Our intriguing finding is that the convectively-stable layer around the neutrinosphere becomes fully-turbulent due to the MRI and its nonlinear penetration into the strongly-stratified MRI-stable region. The intensity of the MRI-driven turbulence increases with magnetic flux threading the core, but is limited by a free energy stored in the differential rotation. The turbulent neutrinosphere is a natural consequence of rotating core-collapse and could exert a positive impact on the supernova mechanism.