Classification of Solar Flares and Relationship between the First and Second Phases,

A large data base on solar flares obtained during the last solar maximum years makes it necessary to revise our views on the relationship between the impulsive phase and the second phase of flares. Contrary to the view most popular before the launch of the Solar Maximum Mission, we now know that relativistic electrons and gamma ray producing protons and ions are accelerated during the impulsive phase. Because flares producing nuclear gamma rays are different from ordinary flares, I conclude that additional processes take place in gamma ray line flares. In my recent studies I have shown that flares with gradual hard X-ray time profiles not only produce nuclear gamma rays during the impulsive phase but alsi develop full-fledged second-phase phenomena. Filament interacts with an overlying flare loop, relativistic electrons and energetic protons are produced during the impulsive phase. When the erupting filament fully distends the overlying flare loop, full fledged second phase. When the erupting filament fully distends the overlying flare loop, full fledged second phase phenomena, such as shocks, interplanetary energetic particles, mass ejections and etc. are observed. When the overlying flare loop is compact and strong enough to suppress the activated filament, gamma rays are emitted during the first phase but no second phase phenomena occur.