The Electrical Breakdown of Gases in Uniform High Frequency Fields at Low Pressure

Abstract

Electrical breakdown in air and in hydrogen for uniform high frequency and static fields was investigated using a pair of geometrically similar electrode systems. Static breakdown potentials for values of pd ≤ 15 mm Hg cm were measured and high frequency data obtained over a range of frequencies f from 5Mc/s to 70Mc/s. The results support the view that there is only one mode of breakdown, contrary to the views proposed by many previous workers. The similarity relationship was found to be satisfied for certain pairs of frequencies provided that the discharge was confined to the regions of uniform field between the electrodes, and that the electrode surfaces were clean. On the other hand, when the electrodes were covered with oxide layers, the similarity theorem did not apply. This result indicates that at least one process of electron generation or loss was not a function of E/p; the most probable process, cold emission, was identified by correlating the results with those obtained under similar conditions with static fields.