MEASUREMENTS OF LONGITUDINAL PRESSURE GRADIENT IN DIRECT-CURRENT DISCHARGES

Measurements have been made of the longitudinal pressure gradient in dc discharges in helium, neon, and argon. Studies have been conducted at current densities ∼ 1 A/cm2, over a pressure range of approximately two orders of magnitude with an accuracy of ± 5μ. Present results when compared at high pressures with calculations based on theory indicate good agreement with Leiby and Oskam's theory by comparison with previous theories of the effect. The studies also indicate an anomalous behavior of the gradient at higher discharge currents in neon and argon.