The problem of small and large scale fields in the solar dynamo

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dc.creatorBrandenburg, A.
dc.creatorHaugen, N. E. L.
dc.creatorKäpylä, P. J.
dc.creatorSandin, C.
dc.date2004-12-15
dc.date.accessioned2026-07-07T02:16:17Z
dc.date.available2026-07-07T02:16:17Z
dc.descriptionThree closely related stumbling blocks of solar mean field dynamo theory are discussed: how dominant are the small scale fields, how is the alpha effect quenched, and whether magnetic and current helicity fluxes alleviate the quenching? It is shown that even at the largest currently available resolution there is no clear evidence of power law scaling of the magnetic and kinetic energy spectra in turbulence. However, using subgrid scale modeling, some indications of asymptotic equipartition can be found. The frequently used first order smoothing approach to calculate the alpha effect and other transport coefficients is contrasted with the superior minimal tau approximation. The possibility of catastrophic alpha quenching is discussed as a result of magnetic helicity conservation. Magnetic and current helicity fluxes are shown to alleviate catastrophic quenching in the presence of shear. Evidence for strong large scale dynamo action, even in the absence of helicity in the forcing, is presented.
dc.descriptionto appear in Astron. Nachr., in honour of the retirement of Michael Stix
dc.identifierhttps://arxiv.org/abs/astro-ph/0412364
dc.identifierhttp://arxiv.org/abs/astro-ph/0412364
dc.identifierAstron.Nachr. 326 (2005) 174-185
dc.identifierdoi:10.1002/asna.200410373
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/8729
dc.subjectAstrophysics
dc.titleThe problem of small and large scale fields in the solar dynamo
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