Three-dimensional simulations of the magnetic stress in a neutron star crust

TL;DR

This paper presents a comprehensive 3D model of neutron star magnetic fields, revealing the persistence of small-scale features and their impact on crustal stresses, with implications for starquake activity over long timescales.

Contribution

It introduces the first fully self-consistent 3D simulation of neutron star magnetic fields driven by the Hall effect, highlighting the survival of small-scale features and their role in crustal stress distribution.

Findings

Global magnetic field converges to a Hall-attractor state.

Small-scale magnetic features persist over long timescales.

Neutron stars with fields >10^{14}G can experience starquakes after 10^5 years.

Abstract

We present the first fully self-consistent three-dimensional model of a neutron star's magnetic field, generated by electric currents in the star's crust via the Hall effect. We find that the global-scale field converges to a Hall-attractor state, as seen in recent axisymmetric models, but that small-scale features in the magnetic field survive even on much longer timescales. These small-scale features propagate toward the dipole equator, where the crustal electric currents organize themselves into a strong equatorial jet. By calculating the distribution of magnetic stresses in the crust, we predict that neutron stars with fields stronger than $10^{14}$G can still be subject to starquakes more than $10^5$yr after their formation.