Double-plasma instability near ion plasma frequency

Summary Form only given, as follows. The instability can be set up in a double-plasma device operated in a simple but unusual mode. In the absence of electron emission from the local filaments, the plasma in the target chamber is simply the diffuse plasma that leaks through the grid from the positively biased source chamber. If the potential of this diffuse target plasma is allowed to be relatively free-ranging, the plasma can be spontaneously into a large amplitude oscillation at a frequency near its ion plasma frequency f/sub pi/. The dependence of the frequency on plasma density, grid bias, source chamber bias, and other parameters has been investigated, and the temporal growth rate of the instability has been measured. The principal results are summarized, and a possible cause of the instability is suggested.<>