The non-linear onset of neutrino-driven convection in two and three-dimensional core-collapse supernovae

TL;DR

This study uses a toy model to explore how turbulence driven by convection develops non-linearly in core-collapse supernovae, highlighting the role of dimensionality, perturbation amplitude, and resolution in the onset of explosion conditions.

Contribution

It demonstrates that 3D simulations produce higher entropy and more turbulent mixing than 2D, influenced by perturbation amplitude and numerical resolution, providing insights into supernova explosion mechanisms.

Findings

3D simulations yield higher entropy than 2D.

Turbulent mixing and dissipation are greater in 3D.

Higher resolution and larger perturbations enhance entropy increase.

Abstract

A toy model of the post-shock region of core-collapse supernovae is used to study the non-linear development of turbulent motions driven by convection in the presence of advection. Our numerical simulations indicate that buoyant perturbations of density are able to trigger self-sustained convection only when the instability is not linearly stabilized by advection. Large amplitude perturbations produced by strong shock oscillations or combustion inhomogeneities before the collapse of the progenitor are efficiently shredded through phase mixing and generate a turbulent cascade. Our model enables us to investigate several physical arguments that had been proposed to explain the impact of the dimensionality on the onset of explosions in global simulations of core-collapse supernovae. Three-dimensional (3D) simulations are found to lead to higher entropy values than two-dimensional (2D) ones. We attribute this to greater turbulent mixing and dissipation of the kinetic energy into heat in 3D. Our results show that the increase of entropy is enhanced with finer numerical resolution and larger perturbation amplitude.