Two-Step Reconnections in a C3.3 Flare and Its Preflare Activity Observed by Hinode XRT

摘要

WeinvestigatedtheevolutionofaC3.3impulsiveflareanditspreflareactivity,whichoccurredinNOAAActiveRegion10923on2006November12,usingHinodeX-RayTelescope(XRT)data.Foranextensiveinvestigation,wealsousedGOESX-rayflux,TRACE171a€‰?…,andSOHOMDIdata.Examiningthetime-seriesoftheXRTandTRACEimages,wecanidentifythefollowingevolutionarysequences:(1)Therewerethreebundlesofloopsalongtheshearedpolarityinversionlineformingasigmoidalstructureduringthepreflarephase.(2)Preflarebrighteningoccurredbetweentwoupper-loopbundles,andtheyconsequentlyformedonelargerbundle.(3)Themainflareoccurrednearthelocationwherethisnewloopbundleandthethirdbundlemettogether.(4)Asaresult,asinglestackedloopstructurewasformed.ThismorphologicalevolutionoftheX-rayloopsisquiteconsistentwithatether-cuttingmodelinvolvingasingle-bipoleexplosion.Ourresultshowsthatthepreflareandthemainflareinthiseventareatwo-stepreconnectionprocess,whichstronglysuggeststhatthepreflareactivityplaysanimportantroleintriggeringthemainflare.