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Solar Physics

, Volume 268, Issue 2, pp 349–362 | Cite as

Newly Identified Properties of Surface Acoustic Power

  • H. SchunkerEmail author
  • D. C. Braun
Open Access
Helioseismology

Abstract

The cause of enhanced acoustic power surrounding active regions, known as the acoustic halo, is not as yet understood. We explore the properties of the enhanced acoustic power observed near disk center from 21 to 27 January 2002, including AR 9787. We find that i) there exists a strong correlation of the enhanced high-frequency power with magnetic-field inclination, with greater power in more horizontal fields, ii) the frequency of the maximum enhancement increases along with magnetic-field strength, and iii) the oscillations contributing to the halos show modal ridges that are shifted to higher wavenumber at constant frequency in comparison to the ridges of modes in the quiet Sun.

Keywords

Helioseismology, observations Active regions, magnetic fields Velocity fields, photosphere 

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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Max Planck Institute for Solar System ResearchKatlenburg-LindauGermany
  2. 2.Colorado Research Associates DivisionNorthWest Research Associates, Inc.BoulderUSA

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