A&A 368, 662-675 (2001)
DOI: 10.1051/0004-6361:20010105
Nonlinear resonant absorption of fast magnetoacoustic waves due to coupling into slow continua in the solar atmosphere
R. Erdélyi1, I. Ballai2 and M. Goossens21 Space & Atmosphere Research Center, Department of Applied Mathematics, University of Sheffield, S3 7RH, Sheffield, UK
2 Center for Plasma-Astrophysics, K.U. Leuven, Celestijnenlaan 200B, 3001 Heverlee, Belgium
(Received 28 July 2000 / Accepted 12 January 2001)
Abstract
Nonlinear resonant absorption of fast magnetoacoustic (FMA) waves
in inhomogeneous weakly dissipative, isotropic and anisotropic
plasmas in static and steady equilibria is studied. Both isotropic
and anisotropic plasmas are considered and for the background
equilibrium state 1D planar static and steady models are
used. The equilibrium configuration consists of three layers,
where an inhomogeneous magnetised plasma slab is surrounded by two
homogeneous magnetised semi-infinite plasma regions. The propagating
FMA waves are partly absorbed due to coupling to local nonlinear slow
magnetohydrodynamic (MHD) waves in the inhomogeneous layer, and are partly
reflected.
The coefficient of wave energy resonant absorption is derived using two
simplifying assumptions (i) weak nonlinearity and (ii) the thickness of the
inhomogeneous layer is small compared to the wavelength of the waves, i.e.
the so-called long-wavelength approximation is used.
Key words: magnetohydrodynamics (MHD) -- Sun: oscillations -- Sun: atmosphere
Offprint request: R. Erdélyi, Robertus@sheffield.ac.uk
© ESO 2001

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