A spectroscopic investigation of moving striations in an argon glow discharge

Abstract

An investigation of moving-striations in an argon glow discharge using a Baird-Atomic Plasma Spectrograph, was conducted to determine the time differences for appearance of spectral lines with different excitation potential. The procedure utilized photographs of oscilloscope traces comparing the 8115A line of argon with the 7372a and 4158a lines. these photographs were analyzed to determine the time differences within the excitations at the points of maximum and minimum intensity. For discharges in a tune of 26.5 mm diameter, with gas pressures in the range of 2mm to 7mmHg pressure, the results indicate the line of lower excitation energy (8115A) leads the higher excitation lines (7372A and 4158A0 by 22 to 30 microseconds at minimum intensity and lags the higher excitation lines by 27 to 35 microseconds at the maximum intensity. It was also noted that the time of intensity rise for the striation was dependent upon the pressure of the gas discharge.