Performance of the Secondary Townsend Emission through the Electric Discharge Characteristics in Coaxial Vircator

Abstract

THE INFLUENCE of secondary electron emission on self sustaining and maintaining discharge current is studied using a new type of DC glow discharge operated on virtual cathode theory through argon gas. The radial electron beam is generated outside the diode in coaxial Vircator. The transported electric discharge, from non-self sustaining to self sustaining discharge, occurs in the Townsend region and strongly depends on the secondary electron emission. The first ionization acts as a breakdown starter, then the second emission completes the electric discharge without consumed energy. The present work aims to study the effect of some physical parameters on the secondary electron emission to reduce the applied breakdown voltage and improve the ionization process, as well as to reduce the consumed electric energy. During the study, it was found that the self discharge started due to the second electron emission (γ) from the cathode which increased by increasing the ionization potential and decreasing the electric field. There was a balance between the first ionization coefficient and the electron attachment which confirms that the ( γ ) is the main element in the glow discharge. The minimum breakdown voltage for argon gas is 219 volts at Pd= 8 x 10-2 Torr.cm.