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.
Surges, peacock tails and microflares
Credit: IRIS, LMSAL/NASA, Juan Martinez Sykora
This long time series of an active region reveals many nice and clear features of great interest within the same observation. On the bottom right at the beginning and end of the observations we see two micro-flares (magnetic energy release most likely associated to magnetic reconnection) which leads to mass ejections into the corona. In the center of the movie one can appreciate small loops that are very dynamic. These short loops were long hypothesized to exist and used to be called "unresolved fine-scale structure" until IRIS observed them for the first time right after launch in 2013. They form a basic building block of the transition region of the Sun, which is sandwiched between the chromosphere and corona. On the right hand side, another type of mass ejection known as a spray surge drifts from left to right. Notice its nice filamentary structure. In addition, above the surge, one can appreciate an oscillating wall with strands known as a "peacock tail". These features are fountains of plasma that are ejected from so-called light bridges, areas in sunspots where the magnetic field is not strong enough to suppress the convection.