Gas temperature measurements in weakly ionized glow discharges with filtered Rayleigh scattering.

Abstract

We report the first gas temperature measurements in plasmas to our knowledge obtained by filtered Rayleigh scattering (FRS). A narrow-linewidth Ti:sapphire laser is used as the illumination source, and a mercury filter provides strong suppression of elastic background. We perform measurements in weakly ionized glow discharges in pure argon and in an argon-plus-1%-nitrogen mixture. Where possible, we verify the FRS technique by comparing filtered measurements with unfiltered measurements. We present point measurements of axial temperature with uncertainties of less than 5%. We use a planar scheme to obtain radial temperature profiles with uncertainties of 10%.