Large electrodeless plasmas at atmospheric pressure sustained by a microwave waveguide

A 1.5-kW 2.45-GHz magnetron source has been used to reliably sustain large electrodless plasmas at atmospheric pressure in a shorted waveguide without a resonator. Working gases have been air, nitrogen, and heated off gases of sulfur containing ores and coal in nitrogen. Various colorful plasmas of value to environmental monitoring and processing applications are generated depending on the composition of the working gas.