The Source Locations of Major Flares and CMEs in Emerging Active Regions

Abstract Major flares and coronal mass ejections (CMEs) tend to originate from compact polarity inversion lines (PILs) in solar active regions (ARs). Recently, a scenario named “collisional shearing” was proposed by Chintzoglou et al. explain the phenomenon, which suggests that collision between different emerging bipoles is able form PIL, driving shearing flux cancellation are responsible for subsequent large activities. In this work, tracking evolution of 19 ARs their birth until they produce first major or CMEs, we investigated source PILs activities, i.e., PILs, explore generality shearing.” We find none self PIL (sPIL) single bipole. further 11 eruptions collisional (cPILs) formed due bipoles, six conjoined systems sPIL cPIL, two ePIL (external AR nearby pre-existing polarities). Collision accompanied found develop at all prior eruptions, with 84% (16/19) cases having length longer than 18 Mm. Moreover, magnitude positively correlated indicating more intense activities severe collisions. The results suggest shearing,” bipole–bipole interaction during emergence, common process ARs.