Superfluid Vortex Lines-Magnetic Flux Tubes Interaction and Braking Indices of Pulsars

TL;DR

This paper investigates how the interaction between superfluid vortex lines and magnetic flux tubes in neutron stars affects pulsar braking indices, revealing dependencies on magnetic field strength and star age.

Contribution

It introduces a detailed analysis of vortex-flux tube interactions and their impact on pulsar spin-down behavior, extending understanding of neutron star rotational evolution.

Findings

Braking index deviations from n=3 depend on magnetic field and age.

Interaction influences magnetic flux expulsion and spin glitches.

Applications to observed pulsars validate the model.

Abstract

Braking of pulsars, or the law of their spin deceleration, is a manifestation of the combination of various processes occurring in the magnetospheres of neutron stars and their internal structural dynamics. The interaction of superfluid neutron vortex lines with superconducting magnetic flux tubes in the neutron star core plays a significant role in rotational evolution and magnetic field evolution through spin glitches and magnetic flux expulsion. In this study, the effect of this interaction on the temporal variation of the braking index of pulsars is investigated. The variation of the deviation from the $n=3$ value predicted by the generally accepted magnetic dipole formula with respect to physical parameters such as the magnetic field and the age of the neutron star has been elaborated, and applications have been made to pulsars with reliably measured braking indices.