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.
Peacock Tails in AR 12804
Credit: IRIS, LMSAL/NASA, Wei Liu
This movie was recorded by IRIS on February 27, 2021 showing active region (AR) 12804 as it approached the west limb with the solar rotation. There were some minor to moderate flaring activity in this AR, especially in its trailing polarity (near the upper left of the movie). More interesting were some episodic brightenings of an arcade of coronal loops on the lower-right edge of this trailing polarity. The brightenings appeared to propagate from lower loops to higher loops along the axis of the arcade (perpendicular to individual loops). This fascinating phenomenon was discovered by IRIS and has been termed "peacock tails". It is believed to be signatures of some shock waves associated with the flare energy release, but the underlying physics is still under investigation.