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Heating of the solar corona by the resonant absorption of Alfven wavesAn improved method for calculating the resonance absorption heating rate is discussed and the results are compared with observations in the solar corona. To accomplish this, the wave equation for a dissipative, compressible plasma is derived from the linearized magnetohydrodynamic equations for a plasma with transverse Alfven speed gradients. For parameters representative of the solar corona, it is found that a two-scale description of the wave motion is appropriate. The large-scale motion, which can be approximated as nearly ideal, has a scale which is on the order of the width of the loop. The small-scale wave, however, has a transverse scale much smaller than the width of the loop, with a width of about 0.3-250 km, and is highly dissipative. These two wave motions are coupled in a narrow resonance region in the loop where the global wave frequency equals the local Alfven wave frequency. Formally, this coupling comes about from using the method of matched asymptotic expansions to match the inner and outer (small and large scale) solutions. The resultant heating rate can be calculated from either of these solutions. A formula derived using the outer (ideal) solution is presented, and shown to be consistent with observations of heating and line broadening in the solar corona.
Document ID
19870057195
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Davila, Joseph M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 13, 2013
Publication Date
June 1, 1987
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 317
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
87A44469
Distribution Limits
Public
Copyright
Other

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