A New Method for Measuring Breakdown and Maintenance Fields in Microwave Discharges

A new experimental approach for comparative measurements of breakdown and maintenance electric fields in microwave discharges is described. The method is based on the analysis of the RF pulses transmitted to a matched load, in absence and in presence of the discharge, by the applicator employed for coupling the RF power to the gas under investigation. Results on breakdown and maintenance field in microwave discharges in nitrogen, at a frequency of 2.45 GHz, for flow and non-flow conditions, in the pressure range 0.5 to 6 torr, are reported.