High-pressure non-equilibrium microwave plasma source by using carbon materials

Abstract

A high-pressure (10 torr atmosphere) microwave plasma was generated in a cavity resonator by using carbon materials [reticulated vitreous carbon (RVC)]. In order to investigate the effect of external parameters, the plasma parameters were measured with both probe and optical methods. The results indicated that this plasma was in non-equilibrium state ( T e≫ T g). The metastable argon atoms and thermal electrons are considered as the important elements in generating this plasma and they were measured by the resonant optical absorption method and by the single probe method, respectively. The electron saturation current with RVC was larger than without it, and the RVC temperature was estimated to be about 2400 K from the Richardson–Dushman equation. The concentration of argon metastable atoms was of the order of 10 10 cm −3 and increased slightly with the argon gas flow.