A novel 2.45 GHz/200 W Microwave Plasma Jet for High Temperature Applications above 3600 K

State of the art atmosphere plasma sources are operated with frequencies in kHz/MHz regions and all high power plasma jets make use of tungsten electrodes. A microwave plasma torch has been developed at FH Aachen for the application in various fields. The advantages over other plasma jet technologies are the high efficiency combined with a maintenance-free compact design and non-tungsten electrodes. In this paper the development of a 200 W torch is described. Argon is used as the primary plasma gas and a second gas can be applied for additional purposes. For the plasma generation a microwave at 2.45 GHz is sent through the torch. The special internal topology causes a high electric field that ignites the plasma at the tip and leads to the ionization of the passing Argon atoms which are emitted as a jet. By designing the copper electrode as a cannula it is possible to gain plasma temperatures higher than the electrode's melting point. The electric field simulations are made with Ansoft HFSS. Experiments were carried out to verify the simulations. The upcoming steps in the development will be the scale-up to higher power levels of several kW with a magnetron as power source.