Abstract
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 10rg. 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.
Original language | English (US) |
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Pages (from-to) | L49-L52 |
Journal | Astrophysical Journal |
Volume | 554 |
Issue number | 1 PART 2 |
DOIs | |
State | Published - Jun 10 2001 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Accretion, accretion disks
- Black hole physics
- Instabilities
- MHD