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dc.contributor.authorFoullon, Claire
dc.contributor.authorFletcher, L.
dc.contributor.authorHannah, Iain G.
dc.contributor.authorVerwichte, E.
dc.contributor.authorCecconi, B.
dc.contributor.authorNakariakov, V.M.
dc.contributor.authorPhillips, K.J.H.
dc.contributor.authorTan, B.L.
dc.date.accessioned2013-08-22T09:10:41Z
dc.date.issued2010
dc.description.abstractLong-period quasi-periodic pulsations (QPPs) of solar flares are a class apart from shorter period events. By involving an external resonator, the mechanism they call upon differs from traditional QPP models, but has wider applications. We present a multi-wavelength analysis of spatially resolved QPPs, with periods around 10 minutes, observed in the X-ray spectrum primarily at energies between 3 and 25 keV. Complementary observations obtained in Hα and radio emission in the kHz to GHz frequency range, together with an analysis of the X-ray plasma properties provide a comprehensive picture that is consistent with a dense flaring loop subject to periodic energization and thermalization. The QPPs obtained in Hα and type III radio bursts, with similar periods as the QPPs in soft X-rays, have the longest periods ever reported for those types of data sets. We also report 1-2 GHz radio emission, concurrent with but unrestricted to the QPP time intervals, which is multi-structured at regularly separated narrowband frequencies and modulated with ~18 minute periods. This radio emission can be attributed to the presence of multiple "quiet" large-scale loops in the background corona. Large scale but shorter inner loops below may act as preferential resonators for the QPPs. The observations support interpretations consistent with both inner and outer loops subject to fast kink magnetohydrodynamic waves. Finally, X-ray imaging indicates the presence of double coronal sources in the flaring sites, which could be the particular signatures of the magnetically linked inner loops. We discuss the preferential conditions and the driving mechanisms causing the repeated flaring.en_GB
dc.identifier.citationVol. 719 (1), pp. 151 - 165en_GB
dc.identifier.doi10.1088/0004-637X/719/1/151
dc.identifier.urihttp://hdl.handle.net/10871/12823
dc.language.isoenen_GB
dc.publisherAmerican Astronomical Society / IOP Publishingen_GB
dc.relation.urlhttp://dx.doi.org/10.1088/0004-637X/719/1/151en_GB
dc.subjectSun: coronaen_GB
dc.subjectSun: flaresen_GB
dc.subjectSun: oscillationsen_GB
dc.subjectSun: particle emissionen_GB
dc.subjectSun: radio radiationen_GB
dc.subjectSun: X-rays, gamma raysen_GB
dc.titleFrom large-scale loops to the sites of dense flaring loops: Preferential conditions for long-period pulsations in solar flaresen_GB
dc.typeArticleen_GB
dc.date.available2013-08-22T09:10:41Z
dc.identifier.issn0004-637X
dc.descriptionCopyright © 2010 American Astronomical Society / IOP Publishingen_GB
dc.identifier.eissn1538-4357
dc.identifier.journalAstrophysical Journalen_GB


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