CMEs are sometimes associated with short periods of explosive energy release, known as solar flares. These flares frequently occur in active regions during the period around solar maximum. An example of a flare associated with an Earthward-directed CME is shown below. Flares have lifetimes ranging from hours for large gradual events down to tens of seconds for the most impulsive events. During solar maximum, approximately one such flare is observed every week.
Flares heat the solar gas to tens of millions of degrees.
The heated gas then radiates strongly across the whole electromagnetic spectrum from radio to gamma rays. The largest of these explosions are so bright that they can even be seen from Earth in visible light. The picture below shows the flare associated with an Earthward-directed CME event which occurred on May 12, 1997. These contribute to the high-energy particle environment in the vicinity of the magnetosphere if Earth's location is magnetically connected to the flaring region by the interplanetary magnetic field. Major flares can be accompanied by energetic protons, which can reach Earth within 30 minutes of the flare's peak.