A convection zone dynamo including the effects of magnetic buoyancy and downward flows
Abstract
A magnetic flux tube may be considered both as a separate body and as a confined field. As a field, it is affected both by the cyclonic convection (-effect) and differential rotation (-effect). As a body, the tube experiences not only a buoyant force, but also a dynamic pressure due to downflows above the tube. When these two dynamic effects are incorporated into the dynamo equations, we obtain a dynamo operating in the convection zone. We analyze and solve the extended dynamo equations in the linear approximation by using observed solar internal rotation and assuming a downflow suggested by numerical simulations of the solar convection zone. The results produce: (i) the 22-year cycle period; (ii) the extended butterfly diagram; (iii) the confinement of strong activity to low heliographic latitudes ; (iv) at low latitudes the radial field is in an approximately phase lag compared to the toroidal field at the same latitude; (v) the poleward branch is in a phase lag with respect to the equatorward branch; (vi) most of the magnetic flux is present in a strongly intermittent form, concentraed into strong flux tubes; (vii) the magnetic field peaks at a depth of ; (viii) total solar irradiance varies in phase with the solar cycle activity, having an amplitude of 0.1%; (ix) solar effective temperature varies in phase with the solar cycle activity, having an amplitude of 1.5 ; and (x) solar radius also varies in phase with the solar cycle activity, having an amplitude of 20 mas. All these results are in agreement with the corresponding observations.
Cite
@article{arxiv.astro-ph/0105393,
title = {A convection zone dynamo including the effects of magnetic buoyancy and downward flows},
author = {L. H. Li and S. Sofia},
journal= {arXiv preprint arXiv:astro-ph/0105393},
year = {2007}
}
Comments
10 pages, 6 figures, 1 table, AASTeX with emulateapj5.sty, this new version uses figures to replace tables, and adds a new section to compare theory with observations, submitted to ApJ