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Oscillations in the Regions of Evershed Flows

Published online by Cambridge University Press:  13 May 2016

D. V. Makarchik
Affiliation:
Institute of Solar-Terrestrial Physics, P.O. Box 4026, Irkutsk, Russia
N. I. Kobanov
Affiliation:
Institute of Solar-Terrestrial Physics, P.O. Box 4026, Irkutsk, Russia

Abstract

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Authors have investigated the line-of-sight velocity difference in the radial direction of sunspot penumbrae simultaneously at two height levels, NiI 4857 and Hβ by the differential method. Power spectra of time series exhibit in the range under consideration three groups of periods: 30-40, 12-15, and 8-10 minutes. Particular emphasis has been placed on the low-frequency portion of the spectrum (0.5-2 mHz). In addition to the 12-minute oscillations as detected by Rimmele the line-of-sight velocity component that is caused by Evershed motion is responsible for oscillations with periods of 15-35 minutes, which occur concurrently at the two height levels.

Type
Session III: Active Region Structure and Dynamics
Copyright
Copyright © Astronomical Society of the Pacific 2001 

References

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