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Changes in Solar Oscillation Frequencies during the Current Activity Maximum: Analysis and Interpretation

Published online by Cambridge University Press:  12 April 2016

W.A. Dziembowski  and
P.R. Goode
W.A. Dziembowski
Affiliation:
Warsaw University Observatory and Copernicus Center, Poland
P.R. Goode
Affiliation:
Big Bear Solar Observatory, New Jersey Institute of Technology, U.S.A

Abstract

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We describe systematic changes in the centroid frequencies and the splitting coefficients as found using data from MDI on board SOHO, covering cycle 23. The data allow us to construct a seismic map of the evolving solar activity - covering all latitudes. At lower latitudes, the temporal evolution closely tracks that of butterfly diagram. The additional information from higher latitudes in the map is of a significant activity in the polar region, peaking at activity minimum in 1996. The most plausible source of solar oscillation frequency changes over the solar cycle is the evolution of the radial component of the small-scale magnetic field. The amplitude of the required mean field changes is ∼ 100 G at the photosphere, and increasing going inward.

Type
Part 4. The Interaction between Convection and Pulsation
Information
International Astronomical Union Colloquium , Volume 185: Radial and Nonradial Pulsations as Probes of Stellar Physics , 2002 , pp. 476 - 479
Copyright
Copyright © Astronomical Society of the Pacific 2002

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