Toward three-dimensional simulations ofstellar core collapse with magnetic fields

摘要

In spherical symmetry, very reliable models of stellar core collapse, bounce, and thepostbounce phase can be constructed based on general relativistic Boltzmann neutrino transport.However, even if the time-integrated neutrino luminosity in the region between the surface ofthe protoneutron star and the stalled accretion shock is one or two orders of magnitude largerthan the energy of a supernova explosion, it is generally accepted that the net energy transferis not efficient enough to drive an explosion, unless the fluid instabilities in this regime aretaken into account. Complementary to other groups, who are elaborating an extension of theaccurate neutrino physics to axisymmetric simulations, we construct efficient parameterizationsof the neutrino physics that enable three-dimensional magneto-hydrodynamics simulations thatdo not constrain the fluid instabilities by artificially imposed symmetries. We evaluate ourapproximations with respect to spherically symmetric Boltzmann neutrino transport, presentpreliminary MHD simulations with a resolution of 600 zones cubed, and illustrate the questionsthat can be addressed by this approach.