Laser Thomson scattering studies of glow discharge plasmas

This paper describes the developments of laser Thomson scattering (LTS) for measuring electron density and temperature, or more generally electron energy distribution function (eedf) in glow discharge plasmas with electron densities below 10 18 m −3 . A brief description of the method for overcoming the sparcity of scattered photons by data accumulation techniques is followed by examples of applications, conducted at the authors' laboratory, to the measurement of the shape of the eedf and temperature anisotropy in various discharges including reactive plasmas, and some as close as 100 μm from a material surface. Measurements of the latter sort should permit the elucidation of micro-discharges and electrode effects such as cathode fall phenomena in particular.