Plasma waves in the laboratory

Abstract

This review presents an overview of wave experiments carried out in laboratory plasmas since 1976. The general trend has been to move away from one dimensional experiments (eg. in Q machines) to experiments with small antennae in large magnetized plasmas involving at least two dimensions. In the main, these experiments involve resonance cone measurements and cyclotron harmonic wave propagation. At larger amplitudes, experiments have been carried out using resonance cones and waves near the electron plasma frequency to investigate the effects arising from the ponderomotive force and from parametric decay. Turbulence - or anomalous resistivity - effects have been studied by propagating large amplitude very narrow pulses through magnetoplasmas. A number of experiments have been made on double layers but their stability still remains somewhat of a mystery. The different results obtained by superficially similar experiments will be discussed in the light of the different methods used to create the plasma. In particular, the difference between Argon and Hydrogen plasmas will be emphasized.