Plasma-volume generation of H⁻ ions in a low-voltage xenon-hydrogen discharge. II

Abstract

A low-voltage xenon-hydrogen discharge is considered theoretically at an interelectrode distance of L = 1 cm and cathode emission current densities of j _s = 2–20 A/cm². Basic parameters of the discharge plasma, in particular, the total hydrogen and xenon densities, are optimized to attain the maximum possible density of negative hydrogen ions $N_{H^ - } (L)$ at the plasma-anode boundary. The distributions of the plasma parameters over the discharge gap are calculated for optimized regimes. According to calculations, at intermediate cathode emission current densities (j _s ≈ 5–10 A/cm²) in optimized discharge regimes, the density of negative hydrogen ions in the anode region of the plasma is $N_{H^ - } (L)$ ≈ (1.5–2.5) × 10¹² cm⁻³ and the total plasma pressure is p ₀ = 0.5–0.6 Torr.