DC Townsend Discharge in Nitrogen: Temperature‐Dependent Phenomena

Abstract

Low-current Townsend discharge in nitrogen has been studied in the temperature range of T = 100-300 K in a semiconductor-gas-discharge structure. It was found that the sustaining voltage U S increases with time when a current is passed through the structure at low T . This effect was not observed at room temperature. A hypothesis is put forward that a film of a neutral phase of nitrogen is formed on the electrodes under cryogenic discharge conditions. The presence of the condensed thin-film phase leads to a decrease in the secondary electron emission from the electrode and to a corresponding increase in US. A possible mechanism of the phenomenon is associated with the formation of large neutral aggregates in the form of [N + 2 (N2)n] − in the gas discharge volume. The condensation of these aggregates seems to yield a phase that is comparatively stable at cryogenic temperatures.