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Dynamo magnetic-field generation in turbulent accretion disksMagnetic fields can play important roles in the dynamics and evolution of accretion disks. The presence of strong differential rotation and vertical density gradients in turbulent disks allows the alpha-omega dynamo mechanism to offset the turbulent dissipation and maintain strong magnetic fields. It is found that MHD dynamo magnetic-field normal modes in an accretion disk are highly localized to restricted regions of a disk. Implications for the character of real, dynamically constrained magnetic fields in accretion disks are discussed. The magnetic stress due to the mean magnetic field is found to be of the order of a viscous stress. The dominant stress, however, is likely to come from small-scale fluctuating magnetic fields. These fields may also give rise to energetic flares above the disk surface, providing a possible explanation for the highly variable hard X-ray emission from objects like Cyg X-l.
Document ID
19910066101
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Stepinski, T. F.
(Lunar and Planetary Institute Houston, TX, United States)
Date Acquired
August 14, 2013
Publication Date
August 1, 1991
Publication Information
Publication: Astronomical Society of the Pacific, Publications
Volume: 103
ISSN: 0004-6280
Subject Category
Astrophysics
Accession Number
91A50724
Funding Number(s)
CONTRACT_GRANT: NASW-4574
Distribution Limits
Public
Copyright
Other

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