Solar flare

A solar flare is an enormous explosion in the solar atmosphere. It results in sudden bursts of particle acceleration, heating of plasma to tens of millions of degrees, and the eruption of large amounts of solar mass. Flares are believed to result from the abrupt release of the energy stored in magnetic fields in the zone around sunspots.
There are two types of flares: impulsive and gradual.

Impulsive flares accelerate mostly electrons, with some protons. They last minutes or hours and the majority appear near the solar equator. Impulsive flares occur at a rate of about 1000 per year during solar maximum.

Gradual flares accelerate electrons, protons, and heavy ions to near the speed of light, and the events tend to last for days. They occur mainly near the poles of the Sun and happen about 100 times per year.

This acceleration of solar flare particles to extremely high energies involves all the different elements in the solar atmosphere. Ions of elements such as carbon, nitrogen, oxygen, neon, magnesium, silicon, and iron, excited in this way, end up in solar cosmic rays, also called solar energetic particles (SEPs).