fr/spaceweather.com:

CANYON OF FIRE: A magnetic filament snaking over the sun’s northeastern limb rose up and erupted during the early hours of Feb. 24th. The eruption split the sun’s atmosphere creating a “canyon of fire,” shown here in a movie captured by the Solar Dynamics Observatory:

The glowing walls of the canyon are formed in a process closely related to that ofarcade loops, which appear after many solar flares. Stretching more than 400,000 km from end to end, the structure traces the original channel where the filament was suspended by magnetic forces above the stellar surface.

As erupting magnetic filaments often do, this one launched a coronal mass ejection (CME) into space. The Solar and Heliospheric Observary recorded the expanding cloud