Neutrino-Driven Convection in Core-Collapse Supernovae: High-Resolution Simulations

TL;DR

This paper uses high-resolution simulations to analyze neutrino-driven convection in core-collapse supernovae, revealing turbulence's role in shock dynamics and emphasizing the importance of resolution for accurate turbulence modeling.

Contribution

It introduces a detailed analysis of turbulence effects on supernova shock evolution and highlights the impact of numerical resolution on turbulence spectra.

Findings

Turbulent convection provides significant pressure support but does not generate net positive energy flux.

An approximate equation predicts shock evolution based on turbulent pressure and non-radial motions.

Higher resolution recovers Kolmogorov turbulence scaling, reducing numerical artifacts.

Abstract

We present results from high-resolution semi-global simulations of neutrino-driven convection in core-collapse supernovae. We employ an idealized setup with parametrized neutrino heating/cooling and nuclear dissociation at the shock front. We study the internal dynamics of neutrino-driven convection and its role in re-distributing energy and momentum through the gain region. We find that even if buoyant plumes are able to locally transfer heat up to the shock, convection is not able to create a net positive energy flux and overcome the downwards transport of energy from the accretion flow. Turbulent convection does, however, provide a significant effective pressure support to the accretion flow as it favors the accumulation of energy, mass and momentum in the gain region. We derive an approximate equation that is able to explain and predict the shock evolution in terms of integrals of quantities such as the turbulent pressure in the gain region or the effects of non-radial motion of the fluid. We use this relation as a way to quantify the role of turbulence in the dynamics of the accretion shock. Finally, we investigate the effects of grid resolution, which we change by a factor 20 between the lowest and highest resolution. Our results show that the shallow slopes of the turbulent kinetic energy spectra reported in previous studies are a numerical artefact. Kolmogorov scaling is progressively recovered as the resolution is increased.