Magnetic field evolution timescales in superconducting neutron stars

TL;DR

This paper extends a magnetic field evolution model to superconducting neutron star cores, revealing accelerated magnetic changes and proposing a hierarchy of evolution timescales that impact observable properties.

Contribution

It generalizes the self-consistent magnetic evolution approach to superconducting cores, highlighting faster evolution and its implications for neutron star observations.

Findings

Magnetic field evolution is significantly accelerated in superconducting cores.

An hierarchy of evolution timescales is proposed for different neutron star stages.

Magnetic fields are not frozen and evolve over observable timescales.

Abstract

The self-consistent approach to the magnetic field evolution in neutron star cores, developed recently, is generalised to the case of superfluid and superconducting neutron stars. Applying this approach to the cold matter of neutron star cores composed of neutrons, protons, electrons, and muons we find that, similarly to the case of normal matter, an arbitrary configuration of the magnetic field may result in generation of macroscopic particle velocities, strongly exceeding their diffusive (relative) velocities. This effect substantially accelerates evolution of the magnetic field in the stellar core. An hierarchy of timescales of such evolution at different stages of neutron star life is proposed and discussed. It is argued that the magnetic field in the core cannot be considered as frozen or vanishing and that its temporal evolution should affect the observational properties of neutron stars.