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