Electron acceleration in solar flares by spatially random DC electric fields, Phys. & Chemist. Earth, 24, 269, 1999


A global model for the acceleration of electrons in the framework of the statistical flare model is presented. In such a model, solar flares are the result of an internal Self-Organised Critical (SOC) process in a complex, evolving, and highly inhomogeneous active region. We have developed a 3D cellular automaton model that simulates flaring activity which extends over an active subflaring background. We derive the spatio-temporal evolution of the active region and the resulting energy release time series, which is associated with an electric field time series. We trace an injected electron distribution in this environment, assuming that the acceleration process is due to randomly placed, localised DC electric fields.
Our numerical results regarding the kinetic energy distribution of the accelerated electrons show a power-law or an exponential behaviour, depending upon the maximum trapping time of the energetic particles inside the acceleration volume.

Keywords: Particle acceleration - Sun: flares