Study of the Characteristics of Cold Ar Atmospheric Pressure Plasma Jet Generated With Inverted Tapered Tube

The atmospheric pressure plasma jet (APPJ) has become one of the hot research issues in plasma science and technology. In this paper, a cold Ar APPJ is generated using a dielectric barrier discharge configuration device equipped with an inverted tapered tube (ITT). Its characteristics are investigated by optical and electrical diagnostics, including discharge images, voltage-current waveforms, and optical emission spectra (OESs). The parameters, such as discharge power, gas temperature, and electronic excitation temperature (EET), are calculated and analyzed. All the above characteristics and parameters are compared with those of Ar APPJ generated with a conventional straight tube (CST). Furthermore, by numerical simulation, the flow field distribution of the ITT and CST is obtained and compared. The results show that the use of the ITT can raise Ar flow velocity, improve the distribution of Ar mole fraction, and Ar flow field. Moreover, the discharge power for the ITT is lower than that for the CST, so are the gas temperature and EET. The difference between theOESs is less obvious. Finally, the plasma plume develops along the inner surface of the CST with bits of apparent filamentary discharge, but along the central axis of the ITT and manifested as a stable and homogeneous discharge, which might be more promising for material processing and biomedical application in some cases.