Magnetic Effect on the Rotation Frequency of a Neutron Star: An Intrinsically Nonlinear Effect

Abstract

A neutron star contains regions with particles which exhibit magnetic moments, which, in turn, generate respective magnetizations. By magnetoelastic interactions between the magnetization and the matter there arises a magnetostriction. The magnetostriction changes the mass density of the neutron star and hence its inertia tensor, and as a result it changes the rotation frequency of the star. It is shown that the effect depends in a distinctly nonlinear way on the magnetization of the neutron star. We also sketch how the calculation of the magnetostriction in the different inner regions of the neutron star has to proceed, and which parameter inputs are needed.