Null Points in the Magnetosphere of a Plunging Neutron Star

TL;DR

This paper investigates the magnetic field structure of a rotating neutron star near a black hole horizon, focusing on null points that are crucial for magnetic reconnection and plasma processes.

Contribution

It provides a detailed analysis of electromagnetic fields near a neutron star in strong gravity, including null point formation and effects of inclination and radiative terms.

Findings

Null points can form in the magnetosphere near a black hole horizon.

Field structure is highly distorted by strong gravity effects.

Null points are relevant for magnetic reconnection in astrophysical plasmas.

Abstract

We explore the structure of a dipole-type vacuum field of a slowly rotating magnetic star near the horizon of a supermassive black hole, where the structure of field lines becomes highly distorted by effects of strong gravity. Such a situation may occur near a neutron star in the final stages of a plunging trajectory into a galactic center. We solve Maxwell's equations in the Rindler approximation for the rotating conducting source of dipolar magnetic field arbitrarily inclined with respect to the axis of rotation. For the fixed inclination angle we calculate the field including the radiative terms while in the general case we discuss the electromagnetic field considering the near-field terms only. In the latter case we investigate the emergence of magnetic null points within the vacuum magnetosphere. Null points become highly relevant in the presence of astrophysical plasma where they are connected with processes of magnetic reconnection and mass ejection.