A New Remote Control Microwave Plasma Jet Excited by Surface Waves

A 2.45-GHz microwave plasma jet (MPJ) is designed based on the excitation of surface plasmon polaritons located in the discharge tube. The unique structure of internal metal antenna with an adjusting screw-pitch gauge is convenient to control plasma discharge at different locations for various gases (Ar, N₂, O₂, and so on) MPJ can be operated at wide pressure range with low incident power. R`egulating the position of the metal antenna and the flow rate, the longest plasma jet of 23 cm is produced at 100 Pa with the operating power of 30 W. As for high pressure, a plasma jet with a length of 7.5 cm is generated 50-cm away from the hole of the waveguide when incident power reaches 50 W. Field analysis is performed using the traditional software, plasma density, electron temperature, and the discharge components are diagnosed analyzed by the Langmuir double probe and spectrograph, respectively. This kind of plasma jet can be achieved for discharge at the desired positions, so it is suitable for the special industrial applications, such as ignition and recombustion for a certain distance.