Simulations of Core Collapse Supernovae In One and Two Dimemsions Using Multigroup Neutrino Transport

In one dimension, we present results from comparisons of stationary state multigroup flux-limited diffusion and Boltzmann neutrino transport, focusing on quantities central to the postbounce shock reheating. In two dimensions, we present results from simulations that couple one-dimensional multigroup flux-limited diffusion to two-dimensional PPM hydrodynamics.Comment: Latex, using sprocl.sty, 3 pages, To appear in the proceedings of the 18th Texas Symposium on Relativistic Astrophysic

Stability of Standing Accretion Shocks, With an Eye Toward Core Collapse Supernovae

We examine the stability of standing, spherical accretion shocks. Accretion shocks arise in core collapse supernovae (the focus of this paper), star formation, and accreting white dwarfs and neutron stars. We present a simple analytic model and use time-dependent hydrodynamics simulations to show that this solution is stable to radial perturbations. In two dimensions we show that small perturbations to a spherical shock front can lead to rapid growth of turbulence behind the shock, driven by the injection of vorticity from the now non-spherical shock. We discuss the ramifications this instability may have for the supernova mechanism.Comment: 21 pages, 13 figures; to be published in The Astrophysical Journa

Conservative formulations of general relativistic kinetic theory

Experience with core-collapse supernova simulations shows that accurate accounting of total particle number and 4-momentum can be a challenge for computational radiative transfer. This accurate accounting would be facilitated by the use of particle number and 4-momentum transport equations that allow transparent conversion between volume and surface integrals in both configuration and momentum space. Such conservative formulations of general relativistic kinetic theory in multiple spatial dimensions are presented in this paper, and their relevance to core-collapse supernova simulations is described.Comment: 48 page