Evolution of the flow field in decaying active regions II. Converging flows at the periphery of naked spots

dc.bibliographicCitation.firstPageA195
dc.bibliographicCitation.journalTitleAstronomy & Astrophysicseng
dc.bibliographicCitation.volume664
dc.contributor.authorStrecker, H.
dc.contributor.authorBello González, N.
dc.date.accessioned2023-02-10T09:22:54Z
dc.date.available2023-02-10T09:22:54Z
dc.date.issued2022
dc.description.abstractContext. In a previous work, we investigated the evolution of the flow field around sunspots during sunspot decay and compared it with the flow field of supergranular cells. The decay of a sunspot proceeds as it interacts with its surroundings. This is manifested by the changes observed in the flow field surrounding the decaying spot. Aims. We now investigate in detail the evolution of the flow field in the direct periphery of the sunspots of the same sample and aim to provide a complete picture of the role of large-scale flows present in sunspot cells. Methods. We analyse the horizontal velocity profiles of sunspots obtained from observations by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). We follow their evolution across the solar disc from their stable phase to their decay and their final disappearance. Results.We find two different scenarios for the evolution of the flow region surrounding a spot in the final stage of its decay: (i) either the flow cell implodes and disappears under the action of the surrounding supergranules or (ii) it outlives the spot. In the later case, an inwards flow towards the remaining naked spot develops in the vicinity closest to the spot followed by an outflow further out. These findings provide observational evidence to theoretical predictions by realistic magnetohydrodynamic (MHD) sunspot and moat region simulations. Conclusions. The Evershed flow and the moat flow, both connected to the presence of fully fledged sunspots in a spot cell, vanish when penumbrae decay. Moat flows decline into supergranular flows. The final fate of a spot cell depends on its interaction with the surrounding supergranular cells. In the case of non-imploding spot cells, the remaining naked spot develops a converging inflow driven by radiative cooling and a geometrical alignment of granules in its periphery which is similar to that observed in pores.eng
dc.description.versionpublishedVersioneng
dc.identifier.urihttps://oa.tib.eu/renate/handle/123456789/11396
dc.identifier.urihttp://dx.doi.org/10.34657/10430
dc.language.isoeng
dc.publisherLes Ulis : EDP Sciences
dc.relation.doihttps://doi.org/10.1051/0004-6361/202142564
dc.relation.essn1432-0746
dc.relation.issn0004-6361
dc.rights.licenseCC BY 4.0 Unported
dc.rights.urihttps://creativecommons.org/licenses/by/4.0
dc.subject.ddc520
dc.subject.otherSun: evolutioneng
dc.subject.otherSun: photosphereeng
dc.subject.othersunspotseng
dc.titleEvolution of the flow field in decaying active regions II. Converging flows at the periphery of naked spotseng
dc.typeArticleeng
dc.typeTexteng
tib.accessRightsopenAccess
wgl.contributorKIS
wgl.subjectPhysikger
wgl.typeZeitschriftenartikelger
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