A kinetic theory based numerical study of core collapse supernova dynamics

The explosion mechanism of core collapse supernovae remains an unsolved problem in astrophysics after many decades of theoretical and numerical study. The complex nature of this problem forces its consideration to rely heavily upon numerical simulations. Current state-of-the-art core collapse supernova simulations typically make use of hydrodynamic codes for the modeling of baryon dynamics coupled to a Boltzmann transport simulation for the neutrinos and other leptons. The results generated by such numerical simulations have given rise to the widely accepted notion that neutrino heating and convection are crucial for the explosion mechanism. However the precise roles that some factors such as neutrinos production and propagation, rotation, three-dimensional effects, the equation of state for asymmetric nuclear matter, general relativity, instabilities, magnetic fields, as well as others play in the explosion mechanism remain to be fully determined. In this work, we review sonic of the current methods used to simulate core collapse supernovae and the various scenarios that have been developed by numerical studies are discussed.;Unlike most of the numerical simulations of core collapse supernovae, we employ a kinetic theory based approach that allows us to explicitly model the propagation of neutrinos and a full ensemble of nuclei. Both of these are significant advantages. The ability to explicitly model the propagation of neutrinos puts their treatment on equal footing with the modeling of baryon dynamics. No simplifying assumptions about the nature of neutrino-matter interactions need to be made and consequently our code is capable of producing output about the flow of neutrinos that most other simulations are inherently incapable of. Furthermore, neutrino flavor oscillations are readily incorporated with our approach. The ability to model the propagation of a full ensemble of nuclei is superior to the standard tracking of free baryons, alpha particles, and a "representative heavy nucleus". Modeling the weak reactions that free baryons and hundreds of species of nuclei undergo results in a more realistic evolution of the nuclear composition. The explicit knowledge of nuclear composition at all times not only allows us to study its evolution in greater detail than it has before, but it also puts us in the unique position to directly model certain nuclear decay modes and the effects that nuclear structure have on non-weak nuclear reaction that occur in supernovae quite straightforwardly.;A systematic study of the influence that electron capture rates and the nuclear equations of state have on the collapse and explosion phase is conducted. The algorithmic implementations and motivations for using the various values and expressions for the electron capture rates and nuclear equations of state are explained and the new forms of output that our code is singularly capable of producing are discussed. Dynamics that may prove to be an entirely new neutrino capture driven explosion mechanism were observed in all of our simulations.