Adaptive Mesh Hydrodynamics of Non-Spherical Core-Collapse Supernovae

We study a hydrodynamic evolution of a non-spherical core-collapse supernova in multidimensions. We begin our study from the moment of shock revival and continue for the first week after explosion when expansion of the supernova ejecta becomes homologous. We observe growth and interaction of Richtmyer-Meshkov, Rayleigh-Taylor, and Kelvin- Helmholtz instabilities resulting in an extensive mixing of the heavy elements throughout the ejecta. We obtain a series of models at progressively higher resolution and provide preliminary discussion of numerical convergence. Unlike in the previous studies, our computations are performed in a single domain. Periodic mesh mapping is avoided. This is made possible by employing an adaptive mesh refinement strategy in which computational workload (defined as a product of the total number of computational cells and the length of the time step) is monitored and, if necessary, limited. Our results are in overall good agreement with the simulations reported by Kifonidis et al. We demonstrate, however, that the amount of mixing and kinematic properties of radioactive species (i.e. 56Ni) is extremely anisotropic. In particular, we find that the model displays a strong tendency to expand laterally away from the equatorial plane toward the poles. Although this behavior is usually attributed to numerical artifacts characteristic of computations with assumed symmetry (axis-effect), the observed behavior can be attributed to a large heat content of the equatorial regions of the explosion model. Future studies are needed to verify that this explosion model property does not have a systematic character.