2001/03/30 by John F. Hawley, Steven A. Balbus, James M. Stone · 163 citations
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Dust and Plasma Wave Phenomena #Instability #Magnetic field #Magnetohydrodynamic drive #Magnetohydrodynamics #Magnetorotational instability #Outflow #Pressure gradient #Torus #astro-ph
paper · pdf · doi:10.1086/320931
published in The Astrophysical Journal 554(1), L49-L52 (IOP Publishing) · 5 pages, 2 figures, submitted to ApJ Letters. For web version and mpeg animations see http://www.astro.virginia.edu/~jh8h/nraf/
arxiv created 2001/03/30 · openalex publication_date 2001/06/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present a global magnetohydrodynamic (MHD) three-dimensional simulation of a nonradiative accretion flow originating in a pressure-supported torus. The evolution is controlled by the magnetorotational instability, which produces turbulence. The flow forms a nearly Keplerian disk. The total pressure scale height in this disk is comparable to the vertical size of the initial torus. Gas pressure dominates near the equator; magnetic pressure is more important in the surrounding atmosphere. A magnetically dominated bound outflow is driven from the disk. The accretion rate through the disk exceeds the final rate into the hole, and a hot torus forms inside 10 r g . Hot gas, pushed up against the centrifugal barrier and confined by magnetic pressure, is ejected in a narrow, unbound, conical outflow. The dynamics are controlled by magnetic turbulence, not thermal convection, and a hydrodynamic α-model is inadequate to describe the flow. The limitations of two-dimensional MHD simulations are also discussed.