Magnetic viscosity in weakly ionized protostellar discs

It has been shown that a self-consistent magnetic dynamo can operate in a fully ionized accretion disc and so provide an effective (magnetic) viscosity. Parker's instability (magnetic buoyancy) in weakly ionized protostellar discs is considered. Combined with the Balbus-Hawley instability in a...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 1997-03, Vol.286 (1), p.97-103
Main Author: Regos, Eniko
Format: Article
Language:English
Subjects:
accretion
accretion discs
instabilities
magnetic fields
stars: formation
Citations: Items that cite this one
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Summary:It has been shown that a self-consistent magnetic dynamo can operate in a fully ionized accretion disc and so provide an effective (magnetic) viscosity. Parker's instability (magnetic buoyancy) in weakly ionized protostellar discs is considered. Combined with the Balbus-Hawley instability in a similar medium, magnetic reconnection and the dynamo model are generalized for weakly ionized discs. The increased rate of reconnection and the decreased growth rate of the Balbus-Hawley instability from increased azimuthal fields have opposite effects. It is found that the Shakura-Sunyaev viscosity parameter does not change for very weakly ionized protostellar accretion discs (αss ∼0.4).
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/286.1.97