Electron Acceleration at Reconnecting X-Points in Solar Flares

The acceleration of electrons in solar flares is simulated using an extended version of a full orbit test-particle code previously used to compute losses of fusion alpha particles from tokamaks and to study flare proton acceleration. The magnetic and electric fields in the model are obtained from solutions of the linearized MHD equations for reconnecting modes at a magnetic X-point with zero equilibrium current. The magnetic field is assumed to have a small finite component perpendicular to the plane of the X-point. The version of the code used in the simulations is fully relativistic and includes Coulomb collisions. It is demonstrated that electrons cross the system boundary at distinct footpoints with the relative numbers and energy distribution at each footpoint sensitive to the longitudinal magnetic field component and collision time. These results are discussed in the context of recent flare observations showing asymmetric hard X-ray emission from the chromospheric footpoints of magnetic loops.

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