Research progress on atmospheric pressure lower-power microwave plasma sources and their application prospects

In comparison with low pressure microwave plasma, atmospheric pressure microwave plasma has some excellent properties such as high density, high activity, simple production equipment, and so on. However, the microwave plasma excited at high gas pressure is often appeared as the form of streamer discharge and the very higher incident power is needed for atmospheric pressure microwave discharges, thence it is difficult in realizing some special applications because of the expensive cost for microwave discharges at atmospheric gas pressure. Aiming at the difficult problem of low power microwave discharge in atmospheric pressure, the research status and application prospect of atmospheric pressure low power microwave plasma source are presented in this paper. Firstly, the research and development status of four kinds of international typical atmospheric pressure low power microwave plasma sources are summarized. Followed the research progress of numerical calculation is introduced. And then the physical mechanism of atmospheric pressure low power microwave discharge is discussed. Finally, several engineering application examples are recommended and their potential applications are prospected.