Title and Abstract

Title:  Eruptive Solar Flares with Parallel and Circular Ribbons                           

Abstract:  Solar flares are among the most powerful energy release events in the solar system, and understanding how they occur so rapidly via magnetic reconnection remains a great challenge in astrophysics and plasma physics. Observational efforts to investigate the flare reconnection often utilize the phenomenon called flare ribbons as the main source of information on the physics of magnetic energy release and other physical quantities in the reconnecting current sheet in the corona. Two distinct sets of ribbons are studied in this regard. One is two parallel ribbons appearing on both sides of the magnetic polarization inversion line, which is understood in terms of magnetic reconnection in either 1D X-point or 2D current sheet. The other type named circular ribbons is found in a special magnetic configuration with a central parasitic magnetic field encompassed by the opposite magnetic polarity fields around, which implies a dome-shaped magnetic fan structure with spine fields in and out of the dome. While the former is more commonly observed and thus considered standard, the latter has also received great attention for being capable of truly 3D magnetic reconnection. This talk will introduce the latest studies of the circular ribbon flares performed by our group, including thermal evolution and subsequent development of current sheet learnt from EUV image analysis, and signature of breakout eruption in microwave maps, as well as standard analyses of vector magnetograms. We also discuss small-scale H-alpha jets from the embedded-bipole structure as a closely related physical process.