Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001apj...554..514s&link_type=abstract
The Astrophysical Journal, Volume 554, Issue 1, pp. 514-527.
Astronomy and Astrophysics
Astronomy
9
Accretion, Accretion Disks, Instabilities, Magnetic Fields, Magnetohydrodynamics: Mhd
Scientific paper
We present the results of global three-dimensional numerical simulations of magnetized accretion disks which have been performed in order to study the evolution of an accretion disk and its surrounding corona within the framework of ideal magnetohydrodynamics. A self-consistent study of this coupled system is a necessary step toward gaining an understanding of both the production and structure of outflows and the angular momentum transport in accretion disks. We study model disks that are initially threaded by a uniform, homogenous magnetic field parallel to the rotational axis. The evolution of these disks is examined under the assumption of an adiabatic equation of state. When the disk is threaded with a weak initial magnetic field, we observe new, intrinsically three-dimensional nonaxisymmetric phenomena that do not occur in the two-dimensional axisymmetric approximation. Our three-dimensional simulations show that in the weak field case MHD waves are generated at the surface of the disk and subsequently propagate into the corona, possibly contributing to coronal heating. To investigate the nature and the origin of these waves, we have performed a series of exploratory simulations with different rotation profiles of the corona and different density relations between disk and corona, as well as simulations with a purely toroidal initial magnetic field. When the simulations are computed with a strong initial field, we find that there is very little difference between two-dimensional and three-dimensional evolution. In both the weak field and strong field cases, in agreement with previous two-dimensional simulations, the disk collapses on orbital timescales. Disk collapse arises from angular momentum transport by the Balbus-Hawley instability in the weak field case and by the external torque of an outflow in the strong field case. We observe the generation of winds in all our simulations. In the weak field case, these winds are unsteady, and they do not collimate within the time frame of the simulation.
Henning Thomas
Steinacker Adriane
No associations
LandOfFree
Global Three-dimensional Magnetohydrodynamic Simulations of Accretion Disks and the Surrounding Magnetosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Global Three-dimensional Magnetohydrodynamic Simulations of Accretion Disks and the Surrounding Magnetosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Global Three-dimensional Magnetohydrodynamic Simulations of Accretion Disks and the Surrounding Magnetosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1581970