Effect of parametric instabilities on entrainment currents: I. Cylindrical plasma systems

The effects of parametric instabilities on the generation of entrainment currents in beam-plasma systems has been studied experimentally and theoretically. The experiments were carried out in a straight cylindrical device with a nonisothermal plasma in which the electron temperature was considerably greater than that of the ions. An external oscillatory electric field with a frequency on the order of the electron plasma frequency initiated decay processes that led to the appearance of high-frequency and ion-acoustic waves. It is shown that the parametrically excited slow hf waves are responsible for the acceleration of electrons and the increase in the current flowing through the plasma. 16 refs., 5 figs.