Zharkov, S., Shelyag, S., Fedun, V. orcid.org/0000-0002-0893-7346 et al. (2 more authors) (2013) Photospheric high-frequency acoustic power excess in sunspot umbra: signature of magneto-acoustic modes. Annales Geophysicae, 31 (8). pp. 1357-1364. ISSN 0992-7689
Abstract
We present observational evidence for the presence of MHD (magnetohydrodynamic) waves in the solar photosphere deduced from SOHO/MDI (Solar and Heliospheric Observatory/Michelson Doppler Imager) Dopplergram velocity observations. The magneto-acoustic perturbations are observed as acoustic power enhancement in the sunspot umbra at high-frequency bands in the velocity component perpendicular to the magnetic field. We use numerical modelling of wave propagation through localised nonuniform magnetic field concentration along with the same filtering procedure as applied to the observations to identify the observed waves. Guided by the results of the numerical simulations we classify the observed oscillations as magnetoacoustic waves excited by the trapped sub-photospheric acoustic waves. We consider the potential application of the presented method as a diagnostic tool for magnetohelioseismology.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Author(s) 2013. CC Attribution 3.0 License. |
Keywords: | Solar physics; astrophysics; and astronomy; magnetic fields; photosphere and chromosphere |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Automatic Control and Systems Engineering (Sheffield) The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 May 2016 08:33 |
Last Modified: | 17 May 2016 08:38 |
Published Version: | http://dx.doi.org/10.5194/angeo-31-1357-2013 |
Status: | Published |
Publisher: | European Geosciences Union |
Refereed: | Yes |
Identification Number: | 10.5194/angeo-31-1357-2013 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:99764 |