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Session 18 - Flares I.
Oral session, Tuesday, July 01
Ballroom A, Chair: Mona Hagyard
We present a model for electron acceleration from thermal to hard X-ray producing energies over the timescale of an energy release fragment in an impulsive solar flare. Fast mode wave acceleration is a relatively new idea which has been examined only under the assumption of isotropizing pitch-angle scattering. We remove this assumption and consider specifically pitch-angle scattering by electron- electron Coulomb collisions. Pitch-angle scattering is important because fast mode waves can only affect the parallel component of the electron momentum and more importantly \dot p_\parallel \propto p_\perp^2, so the energization rate is strongly dependent upon p_\perp. We compare results for the case of no pitch-angle scattering (including Coulomb collisions, but neglecting the transfer of momentum to the perpendicular direction) with those for the case in which Coulomb collisions scatter momentum into the perpendicular direction. We find that pitch-angle scattering strongly enhances the efficiency of fast mode wave acceleration.
Program listing for Tuesday