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.
Small flare on the west solar limb
Credit: IRIS, LMSAL/NASA, Milan Gosic
On December 12, 2022, IRIS was observing active region AR13158 at the west limb. Detecting flares is a difficult task, especially at the solar limb, which requires a little bit of luck. In this particular movie, IRIS captured a small flare while AR13158 was transiting behind the limb. The flare can be seen here as a batch of low-lying bright loops in the lower part of the field of view, indicating magnetic energy that is being released and transferred into heating of the chromosphere and corona. Such observations of active regions provide unique views of the solar activity from the side, rather than from above as when active regions are on the solar disk. The long, red strands are downward-flowing material, known as coronal rain. It represents plasma that was ejected to the corona, rapidly cools off from temperatures of millions of degrees to tens of thousands of degrees, and falls back down to the surface.