Burston, Raymond B.

[["dc.bibliographiccitation.artnumber","A138"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","567"],["dc.contributor.author","Roudier, Thierry"],["dc.contributor.author","Švanda, Michal"],["dc.contributor.author","Rieutord, M."],["dc.contributor.author","Malherbe, J. M."],["dc.contributor.author","Burston, Raymond"],["dc.contributor.author","Gizon, Laurent"],["dc.date.accessioned","2017-09-07T11:48:42Z"],["dc.date.available","2017-09-07T11:48:42Z"],["dc.date.issued","2014"],["dc.description.abstract","Studying the motions on the solar surface is fundamental for understanding how turbulent convection transports energy and how magnetic fields are distributed across the solar surface. From horizontal velocity measurements all over the visible disc of the Sun and using data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI), we investigate the structure and evolution of solar supergranulation. Horizontal velocity fields were measured by following the proper motions of solar granules using a newly developed version of the coherent structure tracking code. With this tool, maps of horizontal divergence were computed. We then segmented and identified supergranular cells and followed their histories by using spatio-temporal labelling. With this data set we derived the fundamental properties of supergranulation, including their motion. We find values of the fundamental parameters of supergranulation similar to previous studies: a mean lifetime of 1.5 days and a mean diameter of 25 Mm. The tracking of individual supergranular cells reveals the solar differential rotation and a poleward circulation trend of the meridional flow. The shape of the derived differential rotation and meridional flow does not depend on the cell size. If there is a background magnetic field, the diverging flows in supergranules are weaker. This study confirms that supergranules are suitable tracers that may be used to investigate the large-scale flows of the solar convection as long as they are detectable enough on the surface."],["dc.identifier.doi","10.1051/0004-6361/201423577"],["dc.identifier.fs","609661"],["dc.identifier.gro","3147039"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10927"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4772"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Structure and evolution of solar supergranulation using SDO/HMI data"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A107"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","595"],["dc.contributor.author","Schunker, H."],["dc.contributor.author","Braun, D. C."],["dc.contributor.author","Birch, A. C."],["dc.contributor.author","Burston, R. B."],["dc.contributor.author","Gizon, L."],["dc.date.accessioned","2017-09-07T11:49:59Z"],["dc.date.available","2017-09-07T11:49:59Z"],["dc.date.issued","2016"],["dc.description.abstract","Context. Observations from the Solar Dynamics Observatory (SDO) have the potential for allowing the helioseismic study of the formation of hundreds of active regions, which would enable us to perform statistical analyses. Aims. Our goal is to collate a uniform data set of emerging active regions observed by the SDO/HMI instrument suitable for helioseismic analysis, where each active region is centred on a 60° × 60° area and can be observed up to seven days before emergence. Methods. We restricted the sample to active regions that were visible in the continuum and emerged into quiet Sun largely avoiding pre-existing magnetic regions. As a reference data set we paired a control region (CR), with the same latitude and distance from central meridian, with each emerging active region (EAR). The control regions do not have any strong emerging flux within 10° of the centre of the map. Each region was tracked at the Carrington rotation rate as it crossed the solar disk, within approximately 65° from the central meridian and up to seven days before, and seven days after, emergence. The mapped and tracked data, consisting of line-of-sight velocity, line-of-sight magnetic field, and intensity as observed by SDO/HMI, are stored in datacubes that are 410 min in duration and spaced 320 min apart. We call this data set, which is currently comprised of 105 emerging active regions observed between May 2010 and November 2012, the SDO Helioseismic Emerging Active Region (SDO/HEAR) survey. Results. To demonstrate the utility of a data set of a large number of emerging active regions, we measure the relative east-west velocity of the leading and trailing polarities from the line-of-sight magnetogram maps during the first day after emergence. The latitudinally averaged line-of-sight magnetic field of all the EARs shows that, on average, the leading (trailing) polarity moves in a prograde (retrograde) direction with a speed of 121 ± 22 m s-1 (−70 ± 13 m s-1) relative to the Carrington rotation rate in the first day. However, relative to the differential rotation of the surface plasma, the east-west velocity is symmetric, with a mean of 95 ± 13 m s-1. Conclusions. The SDO/HEAR data set will not only be useful for helioseismic studies, but will also be useful to study other features such as the surface magnetic field evolution of a large sample of EARs. We intend to extend this survey forwards in time to include more EARs observed by SDO/HMI."],["dc.identifier.doi","10.1051/0004-6361/201628388"],["dc.identifier.gro","3147477"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14279"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5026"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","SDO/HMI survey of emerging active regions for helioseismology"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A113"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","552"],["dc.contributor.author","Roudier, Thierry"],["dc.contributor.author","Rieutord, M."],["dc.contributor.author","Prat, V."],["dc.contributor.author","Malherbe, J. M."],["dc.contributor.author","Renon, N."],["dc.contributor.author","Frank, Z."],["dc.contributor.author","Švanda, Michal"],["dc.contributor.author","Berger, Thomas"],["dc.contributor.author","Burston, Raymond"],["dc.contributor.author","Gizon, Laurent"],["dc.date.accessioned","2017-09-07T11:48:42Z"],["dc.date.available","2017-09-07T11:48:42Z"],["dc.date.issued","2013"],["dc.identifier.doi","10.1051/0004-6361/201220867"],["dc.identifier.gro","3147037"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10134"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4771"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.publisher","EDP Sciences"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Comparison of solar horizontal velocity fields from SDO/HMI and Hinode data"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]