Particle acceleration consequences from fluctuating electric fieldssuperposed on an X-type magnetic field in collisionless solar plasma arestudied. Such a system is chosen to mimic generic features of dynamicreconnection, or the reconnective dissipation of a linear disturbance. Weexplore numerically the consequences for charged particle distributions offluctuating electric fields superposed on an X-type magnetic field. Particledistributions are obtained by numerically integrating individual chargedparticle orbits when a time varying electric field is superimposed on a staticX-type neutral point. This configuration represents the effects of the passageof a generic MHD disturbance through such a system. Different frequencies ofthe electric field are used, representing different possible types of wave. Theelectric field reduces with increasing distance from the X-type neutral pointas in linear dynamic magnetic reconnection. The resulting particledistributions have properties that depend on the amplitude and frequency of theelectric field. In many cases a bimodal form is found. Depending on thetimescale for variation of the electric field, electrons and ions may beaccelerated to different degrees and often have energy distributions ofdifferent forms. Protons are accelerated to $\gamma$-ray producing energies andelectrons to and above hard X-ray producing energies in timescales of 1 second.The acceleration mechanism is possibly important for solar flares and solarnoise storms but is also applicable to all collisionless plasmas.
展开▼
