Open AccessA toy model for magnetic connection in black hole accretion disc
Author(s) -
Wang DingXiong,
Ye YongChun,
Li Yang,
Liu DongMei
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11174.x
Subject(s) - physics , angular momentum , magnetic field , accretion (finance) , black hole (networking) , magnetohydrodynamics , magnetohydrodynamic drive , rotating black hole , magnetic flux , connection (principal bundle) , field line , magnetic energy , kink instability , field (mathematics) , astrophysics , classical mechanics , quantum electrodynamics , magnetization , geometry , quantum mechanics , computer network , routing protocol , routing (electronic design automation) , mathematics , computer science , pure mathematics , link state routing protocol
A toy model for magnetic connection in black hole (BH) accretion disc is discussed based on a poloidal magnetic field generated by a single electric current flowing around a Kerr BH in the equatorial plane. We discuss the effects of the coexistence of two kinds of magnetic connection (MC) arising, respectively, from (1) the closed field lines connecting the BH horizon with the disc (henceforth MCHD) and (2) the closed field lines connecting the plunging region with the disc (henceforth MCPD). The magnetic field configuration is constrained by conservation of magnetic flux and a criterion of the screw instability of the magnetic field. Two parameters λ and α m are introduced to describe our model instead of resolving the complicated magnetohydrodynamic equations. Compared with MCHD, energy and angular momentum of the plunging particles are extracted via MCPD more effectively, provided that the BH spin is not very high. It turns out that negative energy can be delivered to the BH by the plunging particles without violating the second law of BH thermodynamics, however it cannot be realized via MCPD in a stable way.