Dynamo Magnetic Field Modes in Thin Astrophysical Disks: an Adiabatic Computational Approximation
Abstract
An adiabatic approximation is applied to the calculation of turbulent MHD dynamo magnetic fields in thin disks. The adiabatic method is employed to investigate conditions under which magnetic fields generated by disk dynamos permeate the entire disk or are localized to restricted regions of a disk. Two specific cases of Keplerian disks are considered. In the first, magnetic field diffusion is assumed to be dominated by turbulent mixing leading to a dynamo number independent of distance from the center of the disk. In the second, the dynamo number is allowed to vary with distance from the disk's center. Localization of dynamo magnetic field structures is found to be a general feature of disk dynamos, except in the special case of stationary modes in dynamos with constant dynamo number. The implications for the dynamical behavior of dynamo magnetized accretion disks are discussed and the results of these exploratory calculations are examined in the context of the protosolar nebula and accretion disks around compact objects.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1991
- DOI:
- 10.1086/170509
- Bibcode:
- 1991ApJ...379..343S
- Keywords:
-
- Accretion Disks;
- Dynamo Theory;
- Magnetohydrodynamic Turbulence;
- Planetary Evolution;
- Adiabatic Conditions;
- Approximation;
- Magnetic Fields;
- Stellar Mass Accretion;
- Turbulent Mixing;
- Astrophysics;
- HYDROMAGNETICS;
- PLANETS: FORMATION;
- STARS: ACCRETION;
- TURBULENCE