Non-intrusive measurement of axial electric fields in low-pressure glow discharges by velocity modulation laser spectroscopy

Abstract

High resolution (Doppler-resolved) measurement of Doppler-shifted ion absorption frequencies allows the determination of the electric field responsible for the shift. A new method based on velocity modulation laser spectroscopy is described for the nonperturbative measurement of the axial electric fields in glow discharges. The A 'n, + X I&+ (4.0 ) band of NT has heen used as a probe of a He/N, discharge. Half-wave rectification of a sine-wave-driven discharge allows observation of Doppler shifts in the Ion transition frequencies since the ions are traveling in only one direction with respect to the laser wavevector. Electric fields and E/N values have been measured at pressures from 3 to I 1 Torr. Fields in the range of lo-I5 V/cm were observed.

He metastable concentration measurements in a glow discharge

“…Many other experiments with the glow discharge have been performed using copper or other metal electrodes [6]. However we found that stainless steel electrodes are superior in terms of stability and were used throughout the experiments.…”