The dielectric breakdown of gases at low pressure

Abstract The Townsend theory of dielectric breakdown of gases does not apply at low gas density, where the mean free path of electrons maybe of the order of the dimensions of the discharge chamber. An alternative model of breakdown for this region between true gas breakdown and vacuum was presented recently, and shown to apply in the case of mercury vapour. The mathematical model has been extended to lower pressures than previously, and now includes an analysis of possible secondary mechanisms. The theoretical section is complemented by experimental work, again at lower pressures and for a different gas, namely argon. It is shown that the alternative model of breakdown still applies at the lower gas pressures.