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Magnetically Arrested Disk: An Energetically Efficient Accretion Flow

Ramesh Narayan·Igor V. Igumenshchev·Marek A. Abramowicz
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Abstract

We consider an accretion flow model originally proposed by Bisnovatyi-Kogan & 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.

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Ramesh Narayan, Igor V. Igumenshchev, Marek A. Abramowicz. 2003-09-26. Magnetically Arrested Disk: An Energetically Efficient Accretion Flow. https://doi.org/10.1093/pasj%2F55.6.l69

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