Electron acceleration in solar flares Original Research Article

Observations suggest that electron acceleration in impulsive solar flares occurs in magnetic reconnection regions in the corona above the soft X-ray flare loops. Acceleration by a super-Dreicer electric field in a reconnecting current sheet appears to be the most direct way of producing electrons in the energy range between tens of keV and tens of MeV. Theoretical models for collisionless particle acceleration in large-scale current sheets formed in quadrupolar magnetic geometries are reviewed. Recent calculations of particle orbits and energy gains are described, stressing the use of global balance relations and exact MHD solutions for the magnetic fields and plasma flows in the current sheet. The results support the viewpoint that electrons that generate the continuum gamma-ray and hard X-ray emissions in impulsive solar flares are accelerated in a turbulent reconnecting current sheet.