Two-Dimensional Core-Collapse Supernova Simulations with the Isotropic Diffusion Source Approximation for Neutrino Transport

The neutrino mechanism of core-collapse supernova is investigated via non-relativistic, two-dimensional (2D), neutrino radiation-hydrodynamic simulations. For the transport of electron flavor neutrinos, we use the interaction rates defined by Bruenn (1985) and the isotropic diffusion source approximation (IDSA) scheme, which decomposes the transported particles into trapped particle and streaming particle components. Heavy neutrinos are described by a leakage scheme. Unlike the "ray-by-ray" approach in some other multi-dimensional supernova models, we use cylindrical coordinates and solve the trapped particle component in multiple dimensions, improving the proto-neutron star resolution and the neutrino transport in angular and temporal directions. We provide an IDSA verification by performing 1D and 2D simulations with 15 and 20 $M_\odot$ progenitors from Woosley et al.~(2007) and discuss the difference of our IDSA results with those existing in the literature. Additionally, we perform Newtonian 1D and 2D simulations from prebounce core collapse to several hundred milliseconds postbounce with 11, 15, 21, and 27 $M_\odot$ progenitors from Woosley et al.~(2002) with the HS(DD2) equation of state. General relativistic effects are neglected. We obtain robust explosions with diagnostic energies $E_{\rm dig} \gtrsim 0.1- 0.5$~B for all considered 2D models within approximately $100-300$ milliseconds after bounce and find that explosions are mostly dominated by the neutrino-driven convection, although standing accretion shock instabilities are observed as well. We also find that the level of electron deleptonization during collapse dramatically affect the postbounce evolution, e.g.~the ignorance of neutrino-electron scattering during collapse will lead to a stronger explosion.