Generation of High-Power Torch Plasma by a 915-MHz Microwave System

Large electrodeless plasmas at atmospheric pressure have been generated by making use of 915-MHz microwaves from a magnetron operated at high-power source. In comparison with 2450-MHz microwaves, a 915-MHz microwave source induces enlarged plasma based on waveguide. The plasma flames were sustained and stabilized in a discharge tube with an inner diameter of 80 mm by swirl gas flows. When 150-L/min air as a plasma-forming gas was injected, its diameter and length at an applied power of 20 kW were 6.5 and 130 cm, respectively, displaying a flame pillar in its appearance.