Study of Magnetic Reconnection in a Mini-flare with High-resolution Multi-wavelength BBSO Observations

It is generally believed that solar flare onsets are associated with magnetic field reconnection on the solar surface. However, whether full release of the non-potentiality of flux required for eruptive solar activities is still under debate. Using high-resolution multi-wavelength observations taken by BBSO/GST, we investigate triggering mechanisms of the flare, and how much of the free magnetic energy is budgeted through reconncetion. We observed a mini-flare in NOAA 12712 that has spreading ribbons from PIL in aligned positions, forming a ‘mustache’ configuration. Combining Hα and Helium 10830 images with AIA EUV images (131, 171, 193, and 304~Å), we find downstreaming of hot plasma from loop top to footpoints of the flare ribbons, accompanied by disappearance of a fraction of twisted Hα fibrils. NLFFF extrapolation of HMI magnetograms show a confined reconncetion scenario between emerging field of one footpoint and overlying field connecting outer regions while magnetic topology of the flux rope remains intact. The results indicate partial release of non-potential field is sufficient for flare eruptions.