Numerical simulations in astrophysics: Supernovae explosions, magnetorotational model and neutrino emission

Theories of stellar evolution and stellar explosion are based on results of numerical simulations and even qualitative results are not available to ge t analytically. Supernovae are the last stage in the evolution of massive s tars, following the onset of instability, collapse and formation of a neutr on star, Formation of a neutron star is accompanied by a huge amount of ene rgy, approximately 20% of the rest mass energy of the star, but almost all this energy is released in the form of weakly interacting and hardly regist rated neutrino, About 0.1% of the released neutrino energy would be enough for producing a supernovae explosion, but even transformation of such a sma ll part of the neutrino energy into the kinetic energy of matter meets seri ous problems. Two variants are investigated for obtaining explosion. The fi rst one is based on development of convective instability, and more effecti ve heating of the outer layers by a neutrino flux. The second model is based on transformation of a rotational energy of a rap idly rotating neutron star with its envelope into the energy of explosion d ue to action of a magnetic field as a transformation mechanism. Calculation s in this model in 1- and 2-dimensions give a stable value of transformatio n of the rotational energy into the energy of explosion on the level of few percents. This occurrence to be enough for explanation of the energy relea se in supernova explosion. The last model gives a direct demonstration of n onlinear interaction between hydrodynamical and hydromagnetic systems. At f irst a field is amplified by differential rotation, then this enhanced fiel d leads to transformation of the rotational energy into the energy of explo sion.