Flare loops heating by the 0.1–1.0 MeV proton beams

The fast heating of coronal loops at the very beginning of solar flares is discussed as a first observable signature of downstreaming 0.1–1 MeV proton beams. We place emphasis on the produced by proton beams large-scale upward electric field, supporting beam-driven instability of the kinetic Alfvén waves (KAW). The considerable part of a beam kinetic energy may be converted into heat via intermediate KAW with heated region initially spreading from the top downward to footpoints of the loop-like coronal structures with velocity of about a few thousands km/s.