Relaxation of the chiral imbalance and the generation of magnetic fields in magnetars

Abstract: The model for the generation of magnetic fields in a neutron star, based on the magnetic field instability caused by the electroweak interaction between electrons and nucleons, is developed. Using the methods of the quantum field theory, the helicity flip rate of electrons in their scattering off protons in dense matter of a neutron star is calculated. The influence of the electroweak interaction between electrons and background nucleons on the process of the helicity flip is studied. The kinetic equation for the evolution of the chital imbalance is derived. The obtained results are applied for the description of the magnetic fields evolution in magnetars.