The Microwave Admittance of a Mercury-Vapour Discharge

Abstract

The normalized conductance and susceptance of a low-pressure mercury-vapour discharge hare been measured as a function of the discharge current at a frequency of c. 10,000 Mc/s. by a microwave method. The complex conductivity of the discharge is then calculated from the admittance data by representing the discharge as a shunt admittance loading the waveguide. The validity of this approximate representation is examined. The conductivity results are in agreement with similar published results and the similarity between the characteristics of a D.C. sustained discharge and a, radio-frequency discharge are noted. It is deduced that the collision frequency varies only slowly with change in discharge current.