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dc.contributor.authorVerdini, A.
dc.contributor.authorVelli, M.
dc.contributor.authorOughton, Sean
dc.date.accessioned2009-02-10T21:06:36Z
dc.date.available2009-02-10T21:06:36Z
dc.date.issued2005
dc.identifier.citationVerdi, A., Velli, M. & Oughton, S. (2005). Propagation and dissipation of Alfvén waves in stellar atmospheres permeated by isothermal winds. Astronomy & Astrophysics, 444(1), 233-244.en
dc.identifier.urihttps://hdl.handle.net/10289/1999
dc.description.abstractWe investigate the nonlinear evolution of Alfvén waves in a radially stratified isothermal atmosphere with wind, from the atmospheric base out to the Alfvénic point. Nonlinear interactions, triggered by wave reflection due to the atmospheric gradients, are assumed to occur mainly in directions perpendicular to the mean radial magnetic field. The nonlinear coupling between waves propagating in opposite directions is modeled by a phenomenological term, containing an integral turbulent length scale, which acts as a dissipative coefficient for waves of a given frequency. Although the wind acceleration profile is not determined self-consistently one may estimate the dissipation rate inside the layer and follow the evolution of an initial frequency spectrum. Reflection of low frequency waves drives dissipation across the whole spectrum, and steeper gradients, i.e. lower coronal temperatures, enhance the dissipation rate. Moreover, when reasonable wave amplitudes are considered, waves of all frequencies damp at the same rate and the spectrum is not modified substantially during propagation. Therefore the sub-Alfvénic coronal layer acts differently when waves interact nonlinearly, no longer behaving as a frequency dependent filter once reflection-generated nonlinear interactions are included, at least within the classes of models discussed here.en
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherE D P Sciencesen_NZ
dc.rightsThis article has been published in the journal: Astronomy & Astrophysics. ©2005 Astronomy & Astrophysics. Used with permission.en
dc.subjectmagnetohydrodynamicsen
dc.subjectturbulenceen
dc.subjectwavesen
dc.titlePropagation and dissipation of Alfvén waves in stellar atmospheres permeated by isothermal windsen
dc.typeJournal Articleen
dc.identifier.doi10.1051/0004-6361:20052748en
dc.relation.isPartOfAstronomy & Astrophysicsen_NZ
pubs.begin-page233en_NZ
pubs.elements-id31932
pubs.end-page244en_NZ
pubs.issue1en_NZ
pubs.volume444en_NZ


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