Study of a flare and associated surge on solar active region NOAA 11476

C. BUSTOS; LÓPEZ FUENTES, M.C.; MANDRINI, C.H.; POISSON, M.

Conferencia; XI Conferencia Latinoamericana de Geofísica Espacial (XI COLAGE); 2018

We analyze an M4.1 flare and associated surge that occurred in activeregion (AR) NOAA 11476 on 9 May 2012, 21:01 UT. The flare took place at thesame location and approximately 9 hr after the onset of a first more intense(M4.7) event that we studied in a previous work. The AR configuration isextended and mostly bipolar although with some degree of complexity. The siteof both flares coincides with an emerging minor bipole (as observed in SDO/HMIline of sight magnetograms) located in between the two main AR polarities. Thisbipole is observed to rotate by around 150 deg during approximately 36 hsbefore the occurrence of the events, indicating a strong injection of twistinto the overlying coronal magnetic structure. A preliminary study of theevolution of the event, using different EUV bands of the SDO/AIA instrument,suggests a classical quadrupolar configuration with the possible presence of anull point above the emerging twisted bipole. The succession and location ofthe flare brightenings and the surge ejection allows us to determine theapproximate location of the site where the pre-existing structures interact,via magnetic reconnection, with the newly emerging bipole. We will complementour analysis of the event with X-ray data from the Hinode/XRT telescope andlinear force-free extrapolations of the coronal magnetic structure, using asboundary conditions line of sight photospheric magnetograms obtained withSDO/HMI. We will analyze the magnetic model, identifying the presence andlocation of quasi-separatrix layers (QSLs), to interpret the role of thedifferent interacting structures in the triggering and evolution of the event.