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dc.contributor.authorPlatten, S.J.
dc.contributor.authorParnell, C.E.
dc.contributor.authorHaynes, A.L.
dc.contributor.authorPriest, E.R.
dc.contributor.authorMacKay, D.H.
dc.identifier.citationPlatten , S J , Parnell , C E , Haynes , A L , Priest , E R & MacKay , D H 2014 , ' The solar cycle variation of topological structures in the global solar corona ' , Astronomy & Astrophysics , vol. 565 , A44 .
dc.identifier.otherPURE: 143966339
dc.identifier.otherPURE UUID: e144075f-3bbf-4216-9e92-126e4ffccb84
dc.identifier.otherScopus: 84899761861
dc.identifier.otherORCID: /0000-0001-6065-8531/work/58055450
dc.identifier.otherWOS: 000336730900044
dc.identifier.otherORCID: /0000-0002-5694-9069/work/73700747
dc.identifier.otherORCID: /0000-0003-3621-6690/work/74117753
dc.descriptionS.J.P. acknowledges financial support from the Isle of Man Government. E.R.P. is grateful to the Leverhulme Trust for his emeritus fellowship. The research leading to these results has received funding from the European Commission’s Seventh Framework Programme (FP7/2007-2013) under the grant agreement SWIFF (project No. 263340,
dc.description.abstractContext. The complicated distribution of magnetic flux across the solar photosphere results in a complex web of coronal magnetic field structures. To understand this complexity, the magnetic skeleton of the coronal field can be calculated. The skeleton highlights the (separatrix) surfaces that divide the field into topologically distinct regions, allowing open-field regions on the solar surface to be located. Furthermore, separatrix surfaces and their intersections with other separatrix surfaces (i.e., separators) are important likely energy release sites. Aims. The aim of this paper is to investigate, throughout the solar cycle, the nature of coronal magnetic-field topologies that arise under the potential-field source-surface approximation. In particular, we characterise the typical global fields at solar maximum and minimum. Methods. Global magnetic fields are extrapolated from observed Kitt Peak and SOLIS synoptic magnetograms, from Carrington rotations 1645 to 2144, using the potential-field source-surface model. This allows the variations in the coronal skeleton to be studied over three solar cycles. Results. The main building blocks which make up magnetic fields are identified and classified according to the nature of their separatrix surfaces. The magnetic skeleton reveals that, at solar maximum, the global coronal field involves a multitude of topological structures at all latitudes criss-crossing throughout the atmosphere. Many open-field regions exist originating anywhere on the photosphere. At solar minimum, the coronal topology is heavily influenced by the solar magnetic dipole. A strong dipole results in a simple large-scale structure involving just two large polar open-field regions, but, at short radial distances between ± 60° latitude, the small-scale topology is complex. If the solar magnetic dipole if weak, as in the recent minimum, then the low-latitude quiet-sun magnetic fields may be globally significant enough to create many disconnected open-field regions between ± 60° latitude, in addition to the two polar open-field regions.
dc.relation.ispartofAstronomy & Astrophysicsen
dc.rights© ESO, 2014en
dc.subjectSun: activityen
dc.subjectSun: magnetic fieldsen
dc.subjectSun: coronaen
dc.subjectSolar winden
dc.subjectQB Astronomyen
dc.titleThe solar cycle variation of topological structures in the global solar coronaen
dc.typeJournal articleen
dc.contributor.sponsorThe Leverhulme Trusten
dc.contributor.sponsorEuropean Commissionen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. Applied Mathematicsen
dc.contributor.institutionUniversity of St Andrews. School of Mathematics and Statisticsen
dc.contributor.institutionUniversity of St Andrews. Pure Mathematicsen
dc.description.statusPeer revieweden

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