An Electrodeless Discharge at 60 Hz

Inductive flow discharges have been generated in argon at pressures between 0.6 and 3.0 Torr in an 80-mm wide toroidal tube that was threaded by a magnetic core system of 400 cm² cross section. The fields required to maintain the discharges were produced by exciting the core at 60 Hz. Starting was accomplished either by a capacitor discharge through auxiliary electrodes or in an electrodeless manner by exciting the core at 9600 Hz. Plasma currents at 1 Torr exceeded 100A and were slightly trailing the voltage. Mean electron densities at this condition were estimated to be 5×10¹³/cm³. Power dissipation in the discharge was between 0.5 and 1.9 kW at an average conversion efficiency of 60%.