Global anisotropy versus small-scale fluctuations in neutrino flux in core-collapse supernova explosions

Effects of small-scale fluctuations in the neutrino radiation on core-collapse supernova explosions are examined. Through a parameter study with a fixed radiation field of neutrinos, we find substantial differences between the results of globally anisotropic neutrino radiation and those with fluctuations. As the number of modes of fluctuations increases, the shock positions, entropy distributions, and explosion energies approach those of spherical explosion. We conclude that global anisotropy of the neutrino radiation is the most effective mechanism of increasing the explosion energy when the total neutrino luminosity is given. This supports the previous statement on the explosion mechanism by Shimizu and coworkers.