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The effect of ballooning modes on thermal transport and magnetic field diffusion in the solar coronaPresently favored mechanisms of coronal heating (current sheet dissipation and Alfven wave resonant heating) deposit heat in thin layers. Classical thermal conduction cannot explain how heat is transported across the magnetic field. If heating occurs in thin layers, large pressure gradients can be created which can give rise to ballooning modes. These instabilities are caused by the pressure gradient and the curvature of the magnetic field, and are stabilized by magnetic tension. The modes are broad band in wavelength and should produce turbulence. A mixing length expression for the turbulent heat transport shows that it is more than adequate to rapidly convect heat into much broader layers. Furthermore, the turbulent resistivity implies that heating occurs over most of the width of these broadened layers. The broadening also implies that much shorter time scales are required for heating. The beta values in the corona suggest that 1-10 turbulent layers are formed in typical loop or arch structures.
Document ID
19890045671
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Strauss, H. R.
(New York University NY, United States)
Date Acquired
August 14, 2013
Publication Date
March 1, 1989
Publication Information
Publication: Geophysical Research Letters
Volume: 16
ISSN: 0094-8276
Subject Category
Solar Physics
Accession Number
89A33042
Funding Number(s)
CONTRACT_GRANT: NAGW-781
Distribution Limits
Public
Copyright
Other

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