Neutrino interaction with nucleons in the envelope of a collapsing star with a strong magnetic field

The interaction of neutrinos with nucleons in the envelope of a remnant of collapsing system with a strong magnetic field during the passage of the main neutrino flux is investigated. General expressions are derived for the reaction rates and for the energy-momentum transferred to the medium through the neutrino scattering by nucleons and in the direct URCA processes. Parameters of the medium in a strong magnetic field are calculated under the condition of quasi-equilibrium with neutrinos. Numerical estimates are given for the neutrino mean free paths and for the density of the force acting on the envelope along the magnetic field. It is shown that, in a strong toroidal magnetic field, the envelope region partially transparent to neutrinos can acquire a large angular acceleration on the passage time scales of the main neutrino flux.