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.
Violent supersonic upflows in a surge
Credit: IRIS, LMSAL/NASA, Juan Martinez Sykora
This movie shows spectra (on the left) and images (on the right). During the movie, a micro flare occurs which leads to an eruption of gases that is called a surge. This fountain of plasma that is ejected from the Sun can be seen as faint emission in the image on the right. As our slit scans the region, it captures the jet towards the end of the movie. Our spectra reveal that the light is Doppler-shifted towards the blue, i.e., the surge looks like a "satellite" line to the left of the primary bright spectral lines. This indicates strong up flows with supersonic speeds of up to 100km/s in both the cooler chromospheric (Mg II, 10,000K, middle) and transition region (C II, Si IV, 30-100,000 K, left) spectral lines.