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Study of Three-dimensional Magnetic Structure and the Successive Eruptive Nature of Active Region 12371

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dc.contributor.author Vemareddy, P
dc.contributor.author Demoulin, P
dc.date.accessioned 2020-11-11T01:19:11Z
dc.date.available 2020-11-11T01:19:11Z
dc.date.issued 2018-04-20
dc.identifier.citation The Astrophysical Journal, Vol. 857, No. 2, 90 en_US
dc.identifier.issn 0004-637X
dc.identifier.uri http://prints.iiap.res.in/handle/2248/6850
dc.description Restricted Access © The American Astronomical Society; https://doi.org/10.3847/1538-4357/aab6b7 en_US
dc.description.abstract We study the magnetic structure of a successively erupting sigmoid in active region 12371 by modeling the quasi-static coronal field evolution with nonlinear force-free field (NLFFF) equilibria. Helioseismic and Magnetic Imager/Solar Dynamic Observatory vector magnetograms are used as input to the NLFFF model. In all eruption events, the modeled structure resembles the observed pre-eruptive coronal sigmoid and the NLFFF core field is a combination of double inverse-J-shaped and inverse-S field lines with dips touching the photosphere. Such field lines are formed by the flux cancellation reconnection of opposite-J field lines at bald-patch locations, which in turn implies the formation of a weakly twisted flux-rope (FR) from large-scale sheared arcade field lines. Later on, this FR undergoes coronal tether-cutting reconnection until a coronal mass ejection is triggered. The modeled structure captured these major features of sigmoid-to-arcade-to-sigmoid transformation, which is reoccuring under continuous photospheric flux motions. Calculations of the field line twist reveal a fractional increase followed by a decrease of the number of pixels having a range of twist. This traces the buildup process of a twisted core field by slow photospheric motions and the relaxation after eruption, respectively. Our study infers that the large eruptivity of this AR is due to a steep decrease of the background coronal field meeting the torus instability criteria at a low height (≈40 Mm) in contrast to noneruptive ARs. en_US
dc.language.iso en en_US
dc.publisher IOP Publishing en_US
dc.subject Sun: corona en_US
dc.subject Sun: magnetic fields en_US
dc.subject Sun: coronal mass ejections (CMEs) en_US
dc.subject Sun: evolution||Sun: filaments, prominences en_US
dc.subject Sun: flares en_US
dc.title Study of Three-dimensional Magnetic Structure and the Successive Eruptive Nature of Active Region 12371 en_US
dc.type Article en_US


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