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.
Large flare in AR 13289
Credit: IRIS, LMSAL/NASA, Paola Testa
IRIS observed this flare in AR 13289, close to the solar East limb (the flare happened around same time as an M1.8 flare occurred in AR 13288, which is not in the IRIS field of view). The IRIS spectral scan is well timed and proceeds at an ideal pace catching a large portion of the ribbons -- the footpoints of the hot coronal loops-- as well as the overlying hot loops. The ribbons have bright emission in the IRIS chromospheric and transition region lines which are very broad during the flare, indicating large plasma velocities. The hot coronal emission (>10 million degrees K) is visible in the IRIS FeXXI spectral line (at around 1354A, visible for example as a faint and fuzzy blob in the OI window, close to the center of the field of view in the y direction, especially around 11:23:09UT in the IRIS spectral movie), and also very bright in the AIA 94A (mostly dominated by FeXVIII emission) movie shown in the right panel.