The Effect of Neutrino Radiation on Magnetorotational Instability in Proto-Neutron Stars

Neutrino radiation takes a major role in the momentum, heat, and lepton transports in proto-neutron stars (PNSs). These diffusive processes affect the growth of the magnetorotational instability (MRI) in PNSs. We perform a local linear analysis for the axisymmetric and nonaxisymmetric MRI including the effects of neutrino transport and ohmic dissipation. We find that the MRI can grow even in the multidiffusive situations that are realized in neutrino-loaded PNSs. When the toroidal magnetic component dominates over the poloidal one, nonaxisymmetric MRI modes grow much faster than axisymmetric modes. These results suggest the importance of the nonaxisymmetric MRI in PNSs. Thus, understanding the three-dimensional nonlinear evolution of the MRI is necessary for revealing the explosion mechanism of core-collapse supernovae.