Cooperative Thomson scattering from plasma with pulsed CO2 laser radiation

Abstract

An experiment is described in which a 10–20 MW pulsed CO2 laser is used to probe the thermal ion fluctuations in a magnetized argon arc plasma with [Formula: see text], [Formula: see text], and [Formula: see text]. Resolution of scattered ion spectra is achieved with a high finesse infrared Fabry–Perot interferometer. Scattered information is recovered through a multi-shot signal averaging technique which yields a S/N factor of ~ 10 for < μW scattered power levels. Results are compared with spectra calculated from a knowledge of plasma conditions and laser and instrumental linewidths. Demonstration of this diagnostic technique indicates that similar methods could be successfully applied to present magnetically confined fusion research plasmas.