| Abstract : | We present a comprehensive multi-wavelength investigation of four homologous large-scale, blowout-jet solar flares emanating from the fast-evolving part of an active region. The events occurred during a period of ≈ 16 hrs. All the jet-flare events led to not-so-wide coronal mass ejections (angular widths ≈ 95-150º), propagating in the LASCO coronagraphic images with speeds ranging between ≈ 300-500 km/s. Detailed imaging observations at various EUV filter-grams in Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO) reveal that in all the cases, the source region of eruption lies at the boundary of the leading part of a large AR 11515. The eruption originates from the footpoint of a large-scale loop system connecting leading and trailing parts of the AR. In order to explore the cause of homologous large-scale jets, we qualitatively and quantitatively study the process of flux emergence and cancellation in the AR over a period of ≈ 48 hours. We employ a non-linear-force-free-field (NLFFF) model to show the magnetic field topology responsible for the jet eruption and related topological features, such as magnetic flux ropes (MFRs), null points, quasi-separatrix layers (QSLs), etc. Our analysis reveals the drastic and continued emergence of magnetic flux of negative polarity at the leading boundary of AR caused successive interchange magnetic reconnections between the newly formed magnetic loops and pre-existing large-scale loop system. Being at the boundary of the AR, each blowout jet did not experience significant constraining force by overlying field lines, which eventually resulted in CMEs. The study provides important insights on the processes responsible for the continued build-up of magnetic free energy in AR corona, large-scale restructuring of corona and repetitive triggering of space weather events. |
