MPS Seminar: Probing multi-scale processes in solar flares through multi-wavelength observations (B. Joshi)

The contemporary multi-wavelength observations have immensely improved our understanding of the various physical processes occurring in different atmospheric layers of the Sun during a solar flare. The formation of parallel ribbons and associated overlying large post-flare arcades are important signatures which form the basis for the standard 2D model of solar flares. The standard flare model recognizes the flare’s impulsive and intense brightening as consequence of the large-scale magnetic reconnection in a vertical current sheet in the solar corona. In this seminar, I will summarize multi-wavelength observations of solar flares and flare-associated phenomena, outlining the scope and limitations of the standard flare model. The observations of circular ribbon flares (CRF), a morphologically distinct class of solar flares, will also be discussed. In complex manifestations of CRF, the primary event may also exhibit the presence of parallel ribbons, remote ribbons, and jet activity. The typical morphological features and other complexities of such events are discussed in view of the topological structure of a 3D null point; this approach also enable us to explore analogies between the circumstances that govern the onset of jets, confined flares, or CMEs. Some intriguing observations of sub-A-class microflares, occurring outside the active regions, will also be briefly discussed.