Turbulence Generation by Shock-Acoustic-Wave Interaction in Core-Collapse Supernovae

TL;DR

This study investigates how acoustic waves interacting with shocks in core-collapse supernovae generate turbulence, affecting the explosion conditions by slightly reducing the critical neutrino luminosity needed.

Contribution

It extends previous linear perturbation analysis by including acoustic waves, revealing their role in turbulence generation and impact on supernova explosion criteria.

Findings

Vorticity waves contain most turbulent kinetic energy post-shock.

Entropy waves cause density perturbations behind the shock.

Turbulence modestly reduces the critical neutrino luminosity by less than 5%.

Abstract

Convective instabilities in the advanced stages of nuclear shell burning can play an important role in neutrino-driven supernova explosions. In our previous work, we studied the interaction of vorticity and entropy waves with the supernova shock using a linear perturbations theory. In this paper, we extend our work by studying the effect of acoustic waves. As the acoustic waves cross the shock, the perturbed shock induces a field of entropy and vorticity waves in the post-shock flow. We find that, even when the upstream flow is assumed to be dominated by sonic perturbations, the shock-generated vorticity waves contain most of the turbulent kinetic energy in the post-shock region, while the entropy waves produced behind the shock are responsible for most of the density perturbations. The entropy perturbations are expected to become buoyant as a response to the gravity force and then generate additional turbulence in the post-shock region. This leads to a modest reduction of the critical neutrino luminosity necessary for producing an explosion, which we estimate to be less than $ \sim 5 \% $.