Magnetically Arrested Disk: an Energetically Efficient Accretion Flow

We consider an accretion flow model originally proposed by Bisnovatyi-Kogan and Ruzmaikin (1974), which has been confirmed in recent 3D MHD simulations. In the model, the accreting gas drags in a strong poloidal magnetic field to the center such that the accumulated field disrupts the axisymmetric a...

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Bibliographic Details
Published inPublications of the Astronomical Society of Japan Vol. 55; no. 6; pp. L69 - L72
Main Authors Narayan, Ramesh, Igumenshchev, Igor V., Abramowicz, Marek A.
Format Journal Article
LanguageEnglish
Published Oxford, UK Oxford Universtiy Press 25.12.2003
Subjects
quasars: general
magnetic fields
black hole physics
accretion, accretion disks
galaxies: active
galaxies: nuclei
magnetohydrodynamics (MHD)
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Summary:We consider an accretion flow model originally proposed by Bisnovatyi-Kogan and Ruzmaikin (1974), which has been confirmed in recent 3D MHD simulations. In the model, the accreting gas drags in a strong poloidal magnetic field to the center such that the accumulated field disrupts the axisymmetric accretion flow at a relatively large radius. Inside the disruption radius, the gas accretes as discrete blobs or streams with a velocity much less than the free-fall velocity. Almost the entire rest mass energy of the gas is released as heat, radiation and mechanical/magnetic energy. Even for a non-rotating black hole, the efficiency of converting mass to energy is of order 50% or higher. The model is thus a practical analog of an idealized engine proposed by Geroch and Bekenstein.
ISSN:0004-6264
2053-051X
DOI:10.1093/pasj/55.6.L69