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.
Series of A-class solar flares in AR 12857
Credit: IRIS, LMSAL/NASA, Milan Gosic
On 18-Aug-2021 IRIS was observing AR 12857 and captured several A-class flares occurring one after another. They are visible as a sudden flash of light, when a large amount of magnetic energy is released and transferred into heating of the chromosphere and corona. Solar flares are classified according to their intensity, where A-flares are at the lower end of the scale. Yet, they are very important for our understanding of how the solar eruptions are generated, and of the solar activity, which is of paramount importance to our high-tech society. In this movie IRIS shows us four A-class flares and ejected plasma as their consequence. The most prominent are the flares occurring after 10:27 UT. Few seconds after the first flare, we see numerous bright pixels across the images. Those bright pixels are not caused by the flare. They happen whenever high energy particles hit our CCD camera when IRIS is passing through the Earth's radiation belts.