Investigation of small-scale plasma fluctuations by radar backscattering in the upper hybrid resonance

The radar enhanced scattering (RES) diagnostic is shown to be a feasible tool for studying small-scale plasma fluctuations and waves. This method is based on the effect that an RF wave launched into the plasma is considerably slowed down near the hybrid resonance so that the backscattered signal is received with a large time delay. Fairly good spatial and wavenumber resolution of this diagnostic are demonstrated in various laboratory plasmas. (Author)