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.
B-class flare ribbon fills in a supergranule
Credit: IRIS, LMSAL/NASA, Sean Brannon
After a long slumber of solar minimum, the Sun is waking up. As the Sun's magnetic field activity begins to pick up, leading to increased flaring, IRIS is able to capture new and curious events. In this movie, we see an IRIS observation of Active Region (AR) 12791, which was just southwest of disk center in mid-December 2020. A small B-class flare erupts just to the right of the spectrograph slit, resulting in plasma flows along the flare loops in the coronal and a complex pair of flare ribbons make a rough ")(" shape near the flare origin. As the flare evolves, the left-hand member of these ribbons curls back around on itself to make nearly a complete circle enclosing a supergranule. Then, something very interesting happens: the series of brightening events occur inside the ribbon, in a pattern reminiscent of brush fires, until the entire encircled supergranule is filled in.