Abstract Details

Name: Navin Chandra Joshi
Affiliation: Udaipur Solar Observatory, Physical Research Laboratory
Conference ID: ASI2020_162
Title : A complex eruptive circular–cum–parallel ribbon flare triggered by the Successive stages of flux rope eruption
Authors and Co-Authors : Navin Chandra Joshi, Bhuwan Joshi, Prabir K. Mitra
Abstract Type : Oral
Abstract Category : Sun and the Solar System
Abstract : We present multi–wavelength study of a complex M–class solar eruptive flare that consists of three different sets of flare ribbons, viz., circular, parallel, and remote ribbons. Magnetic field modeling of source active region NOAA 12242 exhibits the presence of 3D null–point magnetic topology which encompasses an inner bipolar region. The event begins with the faint signatures of the circular ribbon along with remote brightening right from the pre–flare phase which point toward the ongoing slow yet persistent null–point reconnection. The simultaneous observations of faint parallel ribbon–like brightenings at the footpoints of the low–lying arcades within the fan–dome delineated by the circular ribbon, imply the formation of flux rope during the null–point reconnection likely by the tether-cutting reconnection. Subsequently, with the onset of M8.7 flare, our observations reveal the ongoing null–point reconnection to grow impulsively, triggering the fast restructuring of the inner and outer fan lines, besides the eruption of reconnected field lines. Finally, the eruption of underlying flux rope triggers the standard reconnection beneath it producing an abrupt rise in the intensity of the parallel flare ribbons, as well as, enhances the rate of null–point reconnection. Our analysis suggest that both the torus instability and the breakout model have contribution toward the triggering mechanism for the eruption. This event is a nice example of the dynamical evolution of a flux rope initially confined in a null-point topology, that subsequently activates and erupts with the progression of the circular–cum– parallel ribbon flare.