High energy processes in solar flares

We review the highlights of the high energy processes in solar flares. Particle acceleration is an essential ingredient of the flare energy release process. Among all cosmic high energy sources, hares are unique in that both the accelerated particle and the radiations that they produce are observed. In this paper we emphasize the radiations, gyrosynchrotron emission, bremsstrahlung and gamma ray lines. These provide information on flare models, magnetic fields, energy content in the accelerated particles and abundances. The abundances are not only critical for constraining the acceleration mechanisms, but also provide unique information on solar atmospheric dynamics and mixing, solar wind acceleration, and Galactic chemical evolution.