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.
A Sigmoidal Flare
Credit: IRIS, LMSAL/NASA, SAO, Jakub Prchlik
Sigmoidal Active Regions, named for their S-shaped coronal loops, often produce both flares and eruptions. As such, they are studied to understand the mechanisms that trigger flares and eruptions. Here IRIS observes a sigmoid that produces a M7.3 flare and an eruption. While IRIS does not observe the sigmoidal coronal loops, it does observe a flare ribbon with the characteristic S-shape.