Flare

A rapid release of vast magnetic energy in a sunspot region, causing temperatures to rise tens of millions of degrees in a small area above the solar surface. The resulting radiation surge can cause blackouts of communication signals and damage to satellites. Flares can produce dangerous EUV radiation, X-rays, gamma rays, and high-energy protons.

In solar-terrestrial terms, a sudden eruption of energy on the solar disk lasting minutes to hours, from which radiation and particles are emitted