Effect of hydrogen impurity on the electrical characteristics of neonhyphen;argon gas mixtures. II. Deionization processes in afterglow plasmas

摘要

The effect of small amounts of H2(0.005ndash;1.0percnt;) on the deionization processes in Nehyphen;A discharges was measured by microwave cavity techniques. At low charged particle densities the deionization of discharges produced in Nehyphen;A mixtures is determined by the ambipolar diffusion of electrons and molecular argon ions (A+2). The charged particle density in the deionization period following a pulsed discharge decays exponentially with time. For a discharge tube of 7 mm i.d. filled with Nehyphen;A mixtures at a pressure of thinsp;20 Torr, the deionization of the plasma occurs with a time constant of 1.3 ms. The presence of a small amount of H2(0.005percnt;) enhances the deionization process drastically. The charged particle density decreases much more rapidly (time constant of 0.61 ms) than in the pure mixture. A similar increase in the deionization rate was measured in pure A. At low charge particle densities the deionization rate is determined by the ambipolar diffusion of a highly mobile hydrogen ion, possibly H+3, compared to relatively less mobile argon ions.