The dynamics of charged particles in the near wake of a verynegatively charged body-laboratory experiment and numerical simulation

A numerical simulation that is cylindrical in configuration space and 3-D (v_x, v_y, v_z) in velocity space has been initiated to test a model for the near-wake dynamics of a very negatively charged body, with reference to the plasma environment around spacecraft. The simulation parameters were closely matched to those of a laboratory experiment so that the results may be compared directly. It was found from the laboratory study that the electrons and ions can display different temporal features in the filling-in of the wake; and that they both can be found in the very near-wake region (within one body diameter) of an object with a highly negative body potential. It was also found that the temperature of the electrons in the very near wake could be somewhat colder than the ambient value, suggesting the possibility of a filtering mechanism being operative there. The simulation results to date largely corroborate the density findings in terms of the presence of an enhancement for both ions and electrons and in its location