Parametrically Induced Electron Heating near the Plasma Frequency

The nonlinear saturation and evolution of the parametric instability which occurs near the critical density (microwave frequency, ω₀, equals plasma frequency, ωₚₑ) is studied experimentally. A strong anomalous heating of electrons is observed after the instability saturates. For high powers, a large fraction of the absorbed energy is given to suprathermal electrons. The results may be explained in terms of quasilinear diffusion of electrons in parametrically induced turbulence.