Magnetised Polish doughnuts revisited

TL;DR

This paper presents a method to construct new magnetised equilibrium tori around Kerr black holes, extending previous models by combining different approaches and enabling their use as initial conditions in relativistic MHD simulations.

Contribution

It introduces a novel procedure for building magnetised, equilibrium tori around Kerr black holes that integrates two existing methods and explores their properties.

Findings

New sequences of magnetised tori are constructed.

Models depend on initial parameters and assumptions.

Sequences are suitable as initial data for relativistic MHD simulations.

Abstract

We discuss a procedure to build new sequences of magnetised, equilibrium tori around Kerr black holes which combines two approaches previously considered in the literature. For simplicity we assume that the test-fluid approximation holds, and hence we neglect the self-gravity of the fluid. The models are built assuming a particular form of the angular momentum distribution from which the location and morphology of equipotential surfaces can be computed. This ansatz includes, in particular, the constant angular momentum case originally employed in the construction of thick tori - or Polish doughnuts - and it has already been used to build equilibrium sequences of purely hydrodynamical models. We discuss the properties of the new models and their dependence on the initial parameters. These new sequences can be used as initial data for magnetohydrodynamical evolutions in general relativity.