Changes of plasma potential induced by ion-beam injection

It is experimentally clarified that injection of a stationary ion beam always changes the background plasma potential in a beam-plasma system. In this experiment, a technique of ion energy analysis is adopted to determine the plasma potential in the system. Results show that the plasma potential changes sensitively depending on the beam-to-plasma density ratio, even if other parameters an not allowed to vary. Finally, all the results obtained here are tentatively explained with the help of a Boltzmann relation. (C) 1996 American Institute of Physics.