Laboratory experiments and computer simulations of the interaction of plasmas with rapidly charged objects

The temporal nature of the particle fluxes to conducting objects that are placed in low-density plasmas and then subjected to fast voltage pulses are studied. Experimental measurements of the plasma return current are compared with theoretical predictions and with estimates of the currents obtained from particle-incell computer simulations. By means of the computer simulations, the temporal nature of the kinetic-energy distribution of plasma electrons and ions striking the rapidly biased objects is examined. Likewise, by means of computer simulations and laboratory experiments, the perturbations to the plasmas by the rapidly charged objects is studied. These perturbations include density cavity formation very near the objects caused by particle absorption and particle acceleration and cavitation away from the objects driven by the oscillating two-stream instability