Energy loss of a test charge in partially ionized dusty plasmas

The energy loss of a test charge particle in an unmagnetized dusty plasma i s estimated, by incorporating the dust-neutral collisions. A slowly damping large amplitude wake field is observed which moves ahead of the test charg e position for large dust-neutral collision frequencies. A critical test ch arge velocity is determined for a particular dust-neutral collision frequen cy below which the test charge gains energy instead of losing. The collisio ns enhance the energy loss only for the test charge velocities greater than the dust acoustic speed. (C) 2000 American Institute of Physics. [S1070-66 4X(00)03302-4].