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dc.contributor.authorChorley, N.
dc.contributor.authorFoullon, Claire
dc.contributor.authorHnat, B.
dc.contributor.authorNakariakov, V.M.
dc.contributor.authorShibasaki, K.
dc.date.accessioned2013-08-22T14:24:26Z
dc.date.issued2011
dc.description.abstractLong period oscillations in the microwave radiation intensity generated over the sunspot of NOAA AR 10330 are studied with the Nobeyama Radioheliograph as the sunspot passes over the solar disk, over the course of 9 days (06−15 April 2003). Periodogram, Fourier and global wavelet analyses reveal the presence of a significant oscillatory component in the range P ≈ 50−120 min over the course of the observations. The spectral amplitudes of five significant Fourier components in the range P = 50−150 min are also seen to be stable over the observations, when the data are not affected by changes in magnetic configuration in the region. The ground-based nature of the instrument naturally introduces long data gaps in such long duration observations and the presence of the gaps does not allow any conclusion as to the stability of the phases of the oscillations. As a model to explain the persistence of the dominant long periods, a simple oscillator with a nonlinear driving term is proposed. The spectral difference between distinct peaks within, e.g. the 3 min spectral band, is expected to be able to resonate with the long period one hour oscillations.en_GB
dc.identifier.citationVol. 529, article A123en_GB
dc.identifier.doi10.1051/0004-6361/201116725
dc.identifier.urihttp://hdl.handle.net/10871/12902
dc.language.isoenen_GB
dc.publisherEDP Sciencesen_GB
dc.relation.urlhttp://dx.doi.org/10.1051/0004-6361/201116725en_GB
dc.subjectSun: oscillationsen_GB
dc.subjectSun: activityen_GB
dc.subjectsunspotsen_GB
dc.titlePeriod persistence of long period oscillations in sunspotsen_GB
dc.date.available2013-08-22T14:24:26Z
dc.identifier.issn0004-6361
dc.descriptionCopyright © 2011 ESO / EDP Sciencesen_GB
dc.identifier.eissn1432-0746
dc.identifier.journalAstronomy and Astrophysicsen_GB


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