Larger and more heterogeneous neutron star crusts: A result of strong magnetic fields

Abstract

We study the effect of strong magnetic fields, of the order of ${10}^{15}--{10}^{17}$ G, on the extension of the crust of magnetized neutron stars. The dynamical instability region of neutron-proton-electron $(npe)$ matter at subsaturation densities and the mode with the largest growth rate are determined within a relativistic mean-field model. It is shown that the effect of a strong magnetic field on the instability region is very sensitive to the density dependence of the symmetry energy, and that it is at the origin of an increase of the extension of the crust and of the charge content of clusters.