2-DIMENSIONAL MAPPING OF THE ELECTRIC-FIELD VECTOR IN GLOW-DISCHARGES USING LASER STARK SPECTROSCOPY OF NAK

We have used the laser Stark-induced fluorescence of the NaK molecule to map out the electric field vector in the cathodic sheath of DC glow discharges. The amplitude of the field is deduced from the relative intensities of Stark-mixed laser-induced fluorescence lines, while the direction is deduced from the analysis of their polarization. Numerical solutions of the Poisson equations have also been obtained for the geometry of our discharge cell. By comparison with our experimental results we could infer the potential distribution at the walls in various discharge conditions.