Magnetic layers and neutral points near rotating black hole

TL;DR

This paper investigates how magnetic layers and neutral points form near rotating black holes, highlighting their potential role in magnetic reconnection and the effects of frame-dragging on magnetic field structures.

Contribution

It models the formation of magnetic layers and neutral points near rotating black holes considering oblique fields, frame-dragging, and black hole motion, a novel approach in black hole magnetosphere studies.

Findings

Magnetic layers form near rotating black holes due to field line twisting.

Neutral points are identified as potential sites for magnetic reconnection.

Black hole motion influences the position and structure of magnetic features.

Abstract

Magnetic layers are narrow regions where the field direction changes sharply. They often occur in the association with neutral points of the magnetic field. We show that an organised field can produce these structures near a rotating black hole, and we identify them as potential sites of magnetic reconnection. To that end we study the field lines affected by the frame-dragging effect, twisting the magnetic structure and changing the position of neutral points. We consider oblique fields in vacuum. We also include the possibility of translational motion of the black hole which may be relevant when the black hole is ejected from the system. The model settings apply to the innermost regions around black holes with the ergosphere dominated by a super-equipartition magnetic field and loaded with a negligible gas content.