This TRACE movie contains a sequence of ultraviolet images showing a flare at the solar limb in a chromospheric line (the chromosphere is the region between the photosphere and the transition region/corona) of hydrogen. Hot plasma fills the loops and then falls back down the loops to the limb. A flare is an energetic release of electromagnetic radiation (light) and particles.
This film was taken May 19, 1998 at 1216 Angstroms and was originally located at the TRACE movie page