Fast magnetic field evolution in neutron stars: the key role of magnetically induced fluid motions in the core

TL;DR

This paper presents a method to analyze magnetic field evolution in neutron star cores, revealing that magnetic fields can induce fluid motions much faster than particle diffusion, challenging previous assumptions about the timescale of magnetic evolution.

Contribution

The study introduces a self-consistent approach to compute fluid velocities in neutron star cores, highlighting the significant role of magnetic fields in driving rapid fluid motions.

Findings

Magnetic fields can generate fluid motions exceeding particle diffusion velocities.

The magnetic field evolution timescale may be shorter than previously thought.

The method provides a way to study magnetic and fluid dynamics simultaneously.

Abstract

In [Gusakov et al.\ PRD, 96, 103012, (2017)], we proposed a self-consistent method to study the quasistationary evolution of the magnetic field in neutron-star cores. Here we apply it to calculate the instantaneous particle velocities and other parameters of interest, which are fixed by specifying the magnetic field configuration. Interestingly, we found that the magnetic field can lead to generation of a macroscopic fluid motion with the velocity, significantly exceeding the diffusion particle velocities. This result calls into question the standard view on the magnetic field evolution in neutron stars and suggests a new, shorter timescale for such evolution.