EDP Sciences
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Volume 368, Number 2, March III 2001
Page(s) 662 - 675
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20010105

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. Goossens2

1  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)

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