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The evolution of the Sun's poloidal field

Dikpati, M and Choudhuri, AR (1994) The evolution of the Sun's poloidal field. In: Astronomy and Astrophysics, 291 (3). pp. 975-989.

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We present here a model to explain how the weak large-scale diffuse magnetic fields of the Sun migrate poleward in contrast to the sunspots which migrate equatorward with the progress of the solar cycle. We study the evolution of the Sun's poloidal field in the convection zone by assuming that it is produced by an equatorward-propagating dynamo wave at the base of the convection zone and is then subject to turbulent diffusion and a meridional circulation with a poleward surface flow. The magnetic fieldlines in the lower part of the convection zone first move towards the equator where they are pushed upward by the upwelling meridional flow there to form magnetic bubbles by joining with their opposite hemisphere counterparts. After reaching the surface, these bubbles drift to higher latitudes with the poleward meridional flow. Our model incorporates the three-dimensional vector character of the magnetic field, whereas the previous flux transport models treated the magnetic field as a scalar on the two-dimensional solar surface.

Item Type: Journal Article
Publication: Astronomy and Astrophysics
Publisher: European Southern Observatory
Additional Information: The copyright of this article belongs to European Southern Observatory • Provided by the NASA Astrophysics Data System.
Keywords: Sun;Activity;Magnetic fields;Photosphere
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 05 Sep 2006
Last Modified: 19 Sep 2010 04:30
URI: http://eprints.iisc.ac.in/id/eprint/8141

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