REGULAR AND CHAOTIC ACCELERATION OF ELECTRONS IN RECONNECTING CURRENT SHEETS ON THE SUN

The motion of charged particles in reconnecting current sheets can be either chaotic or regular depending on the magnetic field structure within the current sheet, namely, relative transversal and longitudinal components of the magnetic field. The nonzero transversal magnetic field is responsible for chaotic trajectories, whereas the appreciable longitudinal component suppresses the chaos. In high-temperature current sheets typical for the solar atmosphere the threshold longitudinal component is by an order of magnitude lower than the principal (reconnecting) component. Variations of the longitudinal component may be responsible for the existence of various regimes of electron acceleration observed in solar flares.