The impact of progenitor asymmetries on the neutrino-driven convection in core-collapse supernovae

TL;DR

This study uses 3D simulations to show that pre-collapse asymmetries significantly boost turbulence behind the shock in core-collapse supernovae, aiding explosion mechanisms.

Contribution

It provides the first detailed numerical validation that buoyant density perturbations from progenitor asymmetries enhance post-shock turbulence.

Findings

Density perturbations increase turbulence in the gain region.

Turbulence enhancement depends on perturbation scale and amplitude.

Optimal turbulence occurs when perturbation frequency matches convective turnover frequency.

Abstract

The explosion of massive stars in core-collapse supernovae may be aided by the convective instabilities that develop in their innermost nuclear burning shells. The resulting fluctuations support the explosion by generating additional turbulence behind the supernova shock. It was suggested that the buoyant density perturbations arising from the interaction of the pre-collapse asymmetries with the shock may be the primary contributor to the enhancement of the neutrino-driven turbulent convection in the post-shock region. Employing three-dimensional numerical simulations of a toy model, we investigate the impact of such density perturbations on the post-shock turbulence. We consider a wide range of perturbation parameters. The spatial scale and the amplitude of the perturbations are found to be of comparable importance. The turbulence is particularly enhanced when the perturbation frequency is close to that of the convective turnovers in the gain region. Our analysis confirms that the buoyant density perturbations is indeed the main source of the additional turbulence in the gain region, validating the previous order-of-magnitude estimates.