Charged fluid structures around a rotating compact object with a magnetic dipole field

TL;DR

This paper investigates how rotation of a compact object influences the formation and position of charged fluid structures around it, revealing that rotation enables polar clouds and affects the preference for counter-rotating equatorial tori.

Contribution

It extends previous models by incorporating the rotation of the central object, analyzing its impact on charged fluid structures in a Kerr spacetime with a magnetic dipole field.

Findings

Frame dragging enables polar cloud formation.

Faster rotation favors counter-rotating equatorial tori.

Rotation influences the existence and location of bound fluid structures.

Abstract

We study stationary, electrically charged fluid structures encircling a rotating compact object with a dipole magnetic field oriented along the rotation axis. This situation is described in an idealized way by the Kerr metric and a magnetic dipole "test" field, that does not affect the spacetime. The self-gravitational and self-electromagnetic field of the fluid are neglected and the fluid is assumed to be non conductive and in rigid motion. Our work generalizes a previous study by Kov\'a\v{r} et al.(2016) by taking into account the rotation of the central object. Therefore, we focus on the influence of the rotation onto the existence and position of bound fluid structures. Frame dragging effects allow the existence of polar clouds, which could not be found in non-rotating case. Furthermore counter-rotating equatorial tori become more preferred the faster the central object is spinning.