Open AccessObservations of the Blandford–Znajek process and the magnetohydrodynamic Penrose process in computer simulations of black hole magnetospheres
Author(s) -
Komissarov S. S.
Publication year - 2005
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.1365-2966.2005.08974.x
Subject(s) - physics , rotating black hole , magnetohydrodynamics , black hole (networking) , magnetohydrodynamic drive , penrose process , magnetic field , astrophysics , classical mechanics , kerr metric , quantum electrodynamics , accretion (finance) , schwarzschild radius , quantum mechanics , computer network , routing protocol , de sitter–schwarzschild metric , routing (electronic design automation) , computer science , link state routing protocol
In this paper we report the results of axisymmetric relativistic magnetohydrodynamic (MHD) simulations for the problem of a Kerr black hole immersed in a rarefied plasma with ‘uniform’ magnetic field. The long‐term solution shows properties that are significantly different from those of the initial transient phase studied recently by Koide. The topology of magnetic field lines within the ergosphere is similar to that of the split‐monopole model with a strong current sheet in the equatorial plane. Closer inspection reveals a system of isolated magnetic islands inside the sheet and ongoing magnetic reconnection. No regions of negative hydrodynamic ‘energy at infinity’ are seen inside the ergosphere and the so‐called MHD Penrose process does not operate. However, the rotational energy of the black hole continues to be extracted via the purely electromagnetic Blandford–Znajek mechanism. In spite of this, no strong relativistic outflows from the black hole are seen to be developing. Combined with results of other recent simulations, our results signal a potential problem for the standard MHD model of relativistic astrophysical jets should they be found at distances as small as a few tens of gravitational radii from the central black hole.