Acceleration and orbits of charged particles beneath a monolayer plasma crystal.

Experiments and simulations are reported for a monolayer plasma crystal that is disturbed by an extra particle moving in a plane below the monolayer. Numerical simulations and experiments are performed to find an explanation for the motion of the extra particle. In contrast to earlier simulations where an extra particle did not move spontaneously as in the experiment, here an ion wakefield downstream of the monolayer of particles is included. This resulted in the spontaneous motion of an extra particle as in the experiment, so that it is concluded that the wakefield produces this motion. In both the experiment and the simulation a trend is observed where the orbit of an extra particle becomes more crooked and less energetic when the gas damping is stronger. The simulation reveals that the energy of the extra particle exhibits distinctive transitions between three regimes. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]