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Advection‐dominated solar dynamo model with two‐cell meridional flow and a positive α ‐effect in the tachocline
Author(s) -
Bonanno A.,
Elstner D.,
Belvedere G.
Publication year - 2006
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200610615
Subject(s) - dynamo , convection zone , solar dynamo , meridional flow , tachocline , physics , dynamo theory , convection , geophysics , advection , solar cycle , zonal and meridional , atmospheric sciences , geology , mechanics , magnetic field , solar wind , thermodynamics , quantum mechanics
Most probably the sunspot cycle period is ruled by a meridional flow located near the base of the convection zone (Hathaway et al. 2003). On the other hand, if the eddy diffusivity is low enough, dramatic modification of the standard α 2 Ω ‐dynamo by the meridional flow are expected. In this paper we shall discuss the dependence of periods, dynamo numbers and the sign of the current helicity as a function of the magnetic Reynolds number for a double cell meridional circulation and for a positive α ‐effect at the base of the convection zone. The dynamo action occurs at lower latitudes and its location is at the interface between equatorward and poleward motions near the base of the convection zone. In spite of the complexity of the flow pattern, our simulations show that the resulting dynamo action reproduces several observed features of the solar cycle. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)