Forward and Backward-wave Moving Striations in the Constricted Discharge†

Abstract

In a previous treatment of moving striations in glow discharges, we pointed out that the theory will predict forward-wave striations whenever the striation wavelength is greater than ± -n times the electron thermal relaxation length, and suggested that such waves might be found in high-pressure discharges. Recently forward-wave striations have been reported in the constricted positive column of a high-pressure (35 mm Hg) argon discharge. In this paper, it is shown that starting from measured values of gross discharge parameters and gas properties, the theory predicts waves with properties similar to those observed. Some examples of independent experimental results are given and discussed. It is also shown that the onset of constriction and the appearance of another striation regime are associated with changes in the ion species in the discharge.