Pulsar magnetospheric convulsions induced by an external magnetic field

TL;DR

This paper proposes that external magnetic fields near supermassive black holes can induce instabilities in pulsar magnetospheres, causing magnetic reconnection events that could power fast radio bursts and explain their observed properties.

Contribution

It introduces a novel mechanism where external magnetic fields trigger magnetospheric convulsions in pulsars, linking environmental magnetic strength to FRB generation.

Findings

External magnetic fields can induce magnetospheric instabilities.

Magnetospheric breakage can release energy sufficient for FRBs.

The process explains high rotation measures in FRBs.

Abstract

The canonical pulsar magnetosphere contains a bubble of closed magnetic field lines that is separated from the open lines by current sheets, and different branches of such sheets intersect at a critical line on the light cylinder (LC). The LC is located far away from the neutron star, and the pulsar's intrinsic magnetic field at that location is much weaker than the commonly quoted numbers applicable to the star surface. The magnetic field surrounding supermassive black holes that reside in galactic nuclei is of comparable or greater strength. Therefore, when the pulsar travels inside such regions, a non-negligible Lorentz force is experienced by the current sheets, which tends to pull them apart at the critical line. As breakage occurs, instabilities ensue that burst the bubble, allowing closed field lines to snap open and release large amounts of electromagnetic energy, sufficient to power fast radio bursts (FRBs). This process is necessarily associated with an environment of a strong magnetic field and thus might explain the large rotation measures recorded for the FRBs. We sketch a portrait of the process and examine its compatibility with several other salient features of the FRBs.