Inferring Fundamental Properties of the Flare Current Sheet Using Flare Ribbons: Oscillations in the Reconnection Flux Rates

Recording Q&A: https://www.youtube.com/watch?v=6u_4gov5jE0

Magnetic reconnection is understood to be the main physical process that allows magnetic energy to be transformed into heat, motion, and particle acceleration in solar eruptions. Yet, observational constraints on properties of the reconnection region, and the dynamics that occur there are limited because of the high cadence and spatial resolution needed to capture these during a flare. By studying the evolution and morphology of post-reconnected field-lines footpoints, or flare ribbons, in the 1600 \AA{} Atmospheric Imaging Assembly (AIA) and the Helioseismic Magnetic Imager (HMI) vector photospheric magnetic field, we estimate the magnetic reconnection flux and its rate of change with time to study the energy budget of the reconnection process and dynamics of the current sheet above. We compare high resolution data from the Slit-Jaw Imager (SJI) onboard the Interface Region Imaging Spectrograph (IRIS) with AIA observations to study the evolution of fine-structures in the flare ribbon as they spread away from the polarity inversion line. Using data from 2 M- and X-class flares, we explore the relationship between the ribbon-front fine-structure and the temporal development of bursts in the reconnection region. We quantify this burstiness by quantifying quasi-periodic pulsations (QPPs) signatures in derived reconnection rates. Additionally, we use the RibbonDB database to perform statistical analysis of 73 C- to X-class flares and identify QPP’s properties using the Automated Flare Inference of Oscillations (AFINO) method.  We find that the oscillations’ periods range from one to eleven minutes. We discuss the physical implication of our finding and discuss future observational studies that could help us further constrain the current sheet dynamics.