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Leaky and resonantly damped flux tube modes reconsidered
H. Stenuit 1,
W.J. Tirry * 1,
R. Keppens 2 and
M. Goossens 1
Received 20 April 1998 / Accepted 3 November 1998
In this research note the results for the eigenfrequencies of the uniform and non-uniform magnetic flux tubes of Stenuit et al. (1998) are reconsidered. In that paper it is shown that the eigenfrequencies may have a damping rate due to two mechanisms causing a loss of energy. In non-uniform flux tubes the eigenmodes can be damped by resonant absorption. The other mechanism is leakage of wave energy into the surroundings, which can occur for both uniform and non-uniform flux tubes.
We point out that the dispersion relations obtained by Stenuit et al. are correct for leaky and undamped non-leaky modes, but are not correct for resonantly damped non-leaky modes.
Key words: Magnetohydrodynamics (MHD) Sun: oscillations Sun: photosphere Sun: sunspots
Send offprint requests to: H. Stenuit
Online publication: February 23, 1999