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Title: A potential thermal dynamo and its astrophysical applications

Authors:
;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1254342
Grant/Contract Number:
AC02-09CH-11466
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Related Information: CHORUS Timestamp: 2016-12-26 19:17:33; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Lingam, Manasvi, and Mahajan, Swadesh M. A potential thermal dynamo and its astrophysical applications. United States: N. p., 2016. Web. doi:10.1063/1.4951725.
Lingam, Manasvi, & Mahajan, Swadesh M. A potential thermal dynamo and its astrophysical applications. United States. doi:10.1063/1.4951725.
Lingam, Manasvi, and Mahajan, Swadesh M. 2016. "A potential thermal dynamo and its astrophysical applications". United States. doi:10.1063/1.4951725.
@article{osti_1254342,
title = {A potential thermal dynamo and its astrophysical applications},
author = {Lingam, Manasvi and Mahajan, Swadesh M.},
abstractNote = {},
doi = {10.1063/1.4951725},
journal = {Physics of Plasmas},
number = 5,
volume = 23,
place = {United States},
year = 2016,
month = 5
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4951725

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  • It is shown that thermal turbulence, not unlike the standard kinetic and magnetic turbulence, can be an effective driver of a mean-field dynamo. In simple models, such as hydrodynamics and magnetohydrodynamics, both vorticity and induction equations can have strong thermal drives that resemble the α and γ effects in conventional dynamo theories; the thermal drives are likely to be dominant in systems that are endowed with subsonic, low-β turbulence. A pure thermal dynamo is quite different from the conventional dynamo in which the same kinetic/magnetic mix in the ambient turbulence can yield a different ratio of macroscopic magnetic/vortical fields. Themore » possible implications of the similarities and differences between the thermal and non-thermal dynamos are discussed. The thermal dynamo is shown to be highly important in the stellar and planetary context, and yields results broadly consistent with other theoretical and experimental approaches.« less
  • A computational method for treating the generation of dynamo magnetic fields in astrophysical disks is presented. The numerical difficulty of handling the boundary condition at infinity in the cylindrical disk geometry is overcome by embedding the disk in a spherical computational space and matching the solutions to analytically tractable spherical functions in the surrounding space. The lowest lying dynamo normal modes for a thick astrophysical disk are calculated. The generated modes found are all oscillatory and spatially localized. Tha potential implications of the results for the properties of dynamo magnetic fields in real astrophysical disks are discussed. 30 references.