Magnetic connection and current distribution in black hole accretion discs

TL;DR

This paper explores the origins of large-scale magnetic fields in black hole accretion discs, identifying four magnetic connection configurations and linking them to phenomena like the Blandford-Znajek process and quasi-periodic oscillations.

Contribution

It introduces a unified model of magnetic connection types in black hole discs based on current distributions, connecting these to observed astrophysical processes.

Findings

Four magnetic connection configurations identified

Blandford-Znajek process as a magnetic connection type

Proposed scenario for quasi-periodic oscillations

Abstract

We discuss one of the possible origins of large-scale magnetic fields based on a continuous distribution of toroidal electric current flowing in the inner region of the disc around a Kerr black hole (BH) in the framework of general relativity. It turns out that four types of configuration of the magnetic connection (MC) are generated, i.e., MC of the BH with the remote astrophysical load (MCHL), MC of the BH with the disc (MCHD), MC of the plunging region with the disc (MCPD) and MC of the inner and outer disc regions (MCDD). It turns out that the Blandford-Znajek (BZ) process can be regarded as one type of MC, i.e., MCHL. In addition, we propose a scenario for fitting the quasi-periodic oscillations in BH binaries based on MCDD associated with the magnetic reconnection.