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Resonant behaviour of MHD waves on magnetic flux tubes. I - Connection formulae at the resonant surfaces. II - Absorption of sound waves by sunspotsThe present method of addressing the resonance problems that emerge in such MHD phenomena as the resonant absorption of waves at the Alfven resonance point avoids solving the fourth-order differential equation of dissipative MHD by recourse to connection formulae across the dissipation layer. In the second part of this investigation, the absorption of solar 5-min oscillations by sunspots is interpreted as the resonant absorption of sounds by a magnetic cylinder. The absorption coefficient is interpreted (1) analytically, under certain simplifying assumptions, and numerically, under more general conditions. The observed absorption coefficient magnitude is explained over suitable parameter ranges.
Document ID
19910059815
Document Type
Reprint (Version printed in journal)
Authors
Sakurai, Takashi (National Astronomical Observatory Mitaka, Japan)
Goossens, Marcel (Leuven, Katholieke Universiteit Louvain, Belgium)
Hollweg, Joseph V. (New Hampshire, University Durham, United States)
Date Acquired
August 15, 2013
Publication Date
June 1, 1991
Publication Information
Publication: Solar Physics
Volume: 133
ISSN: 0038-0938
Subject Category
SOLAR PHYSICS
Funding Number(s)
CONTRACT_GRANT: NAGW-76
CONTRACT_GRANT: NSG-7411
Distribution Limits
Public
Copyright
Other