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Astron. Astrophys. 362, 1151-1157 (2000)


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Slow magnetoacoustic waves in coronal loops

V.M. Nakariakov 1, E. Verwichte 2, D. Berghmans 2 and E. Robbrecht 2,3

1 Physics Department, University of Warwick, Coventry CV4 7AL, UK (valery@astro.warwick.ac.uk)
2 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium (Erwin.Verwichte@ksb-orb.oma.be)
3 Centre for Plasma Astrophysics, K. U. Leuven, Celestijnenlaan 200B, 3001 Heverlee, Belgium

Received 29 June 2000 / Accepted 31 August 2000

Abstract

A theoretical model interpreting propagating disturbances of EUV emission intensity, recently observed in coronal loops, is constructed in terms of slow magnetoacoustic waves. The model is one-dimensional and incorporates effects of nonlinearity, dissipation due to finite viscosity and thermal conduction, and gravitational stratification of plasma in the loop. It has been found that, for the observationally detected parameters of the waves, the main factors influencing the wave evolution are dissipation and stratification. The upwardly propagating waves of observed periods (5-20 min) are found to decay significantly in the vicinity of the loop apex, explaining the rarity of observational detection of downwardly propagating waves. The model provides a theoretical basis for development of MHD seismology of the coronal loops.

Key words: Magnetohydrodynamics (MHD) – waves – Sun: activity – Sun: corona – Sun: oscillations – Sun: UV radiation

Send offprint requests to: V.M. Nakariakov

© European Southern Observatory (ESO) 2000

Online publication: October 30, 2000

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