Magnetic Field Instability Driven by Anomalous Magnetic Moments of Massive Fermions and the Electroweak Interaction with Background Matter

It has been shown that the electric current of massive fermions can be excited along an external magnetic field when particles have anomalous magnetic moments and undergo the electroweak interaction with background matter. This current has been calculated on the basis of the exact solution of the Dirac equation in external fields. It has been shown that the magnetic field becomes unstable if this current is included in Maxwell’s equations. It has been found that the seed magnetic field can be significantly enhanced in the particular case of a degenerate electron gas existing in a neutron star. The astrophysical applications of the results have been discussed.