A major solar flare triggered off a sort of tidal wave on the visible face of the Sun. The event was detected by the new solar patrol telescope in New Mexico on the 6th of December. This phenomenon is impressive and you can see it quickly covering a large distance (a few hundreds thousand kilometers here) in a matter of minutes (around 8 minutes).
This phenomenon, known since the sixties, is called moreton wave, which is named after the astronomer Gay Moreton.
Source: National Solar Observatory & Wikipedia