Efficiency of electron-beam energy deposition in a beam-plasma discharge

Electron-beam energy deposition in a steady-state beam-plasma discharge is studied experimentally. The discharge is excited in a longitudinal magnetic field in a parameter range that is of interest for applications. It is shown that, when an external RF electric field at a frequency lying between the low-hybrid and ion plasma frequencies is applied to a plasma with a density of similar to 10(11) cm(-3) created by a relatively intense electron beam with density n(b) similar to 10(8) cm(-3), a strong plasma turbulence develops, which significantly affects the beam relaxation. The data obtained on the beam and plasma parameters and on the spectra of low-frequency oscillations allow one to estimate the effective amplitude of the RF field in a plasma and give better insight into the processes governing the spectra of low-frequency oscillations in a plasma with crossed magnetic and RF electric fields.