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 5%.