IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
Precursors and ribbon evolution in a B-class flare
Credit: IRIS, LMSAL/NASA, Planner: Vanessa Polito
Even smaller events, like this B2.5 class flare observed by IRIS on January 29th 2021, can show puzzling and interesting features. As observed in many large flares, also this small flare was preceded by some precursor activity, such as compact plasma brightening and flows. A curious feature is the evolution of the leftmost ribbon, which seems to be composed of two initially separate sections, that later are joined together. Such puzzling dynamics can provide crucial observational constraints for the standard flare models in 3D.