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The Sun's Rotation Rate as Inferred from Magnetic Field Data

Published online by Cambridge University Press:  08 February 2017

J.O. Stenflo*
Affiliation:
Institute of Astronomy ETH-Zentrum, CH-8092 Zürich Switzerland

Abstract

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The pattern of solar magnetic fields has been used as a tracer to determine how the sun's rotation rate varies with latitude and time. Two distinctly different rotation laws emerge from such an analysis, one agreeing with the surface Doppler rotation rate, the other corresponding to much more rigid rotation with a small polar spin-up. Detailed analysis shows that this second law cannot be explained in terms of flux redistribution on the solar surface, but that it represents the rotation properties of the sources of magnetic flux, which are likely to be located at the bottom of the convection zone.

The rotational phase velocity of the source pattern is found to be constant with time, which suggests that the depth at which the magnetic flux is stored and amplified inside the sun does not vary with the solar cycle, and that the phase velocity also represents the plasma velocity.

Type
V. Large-scale Structure and Dynamics
Copyright
Copyright © Kluwer 1990 

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