Solar flares as sources of energetic particles

A review is presented of the present state of knowledge of solar flare phenomena with special emphasis on the production of suprathermal particles and their solar effects. Of these energetic particles electrons play an important role, since they produce the X-ray and radio bursts observed during many flares. Also, during their slowing down to thermal energies they contribute to the heating of localized regions in the solar atmosphere, through energy exchange with the ambient electrons. Observable radiations of energetic protons, and other nuclei, are produced through nuclear interactions leading to the emissions of gamma-ray lines. Detectable fluxes of these gamma-ray lines are produced only in the most powerful flares. Also the nuclei that enter into deeper layers of the solar atmosphere transfer most of their kinetic energy to the ambient plasma.