| In recent years, with the development of society and the progress of science and technology, cold plasma jets generated in atmospheric pressure discharges represent a rapidly developing technology, which have attracted much attention. Today, this technology is still a research hotspot. Moreover, atmospheric pressure cold plasma jets have the properties of low temperature, good controllability as well as simplicity of operation, which make them promising for some areas, such as traditional materials processing, environmental engineering and plasma chemistry. As we know, the applications of plasma are based on its characteristic study, thus it is both important and essential to obtain the parameters of plasma. Basing on this, the main research work can be described as:A cold helium plasma jets developed by a specially designed device consisting of one powered electrode and one grounded ring electrode, which is actually based on a DBD configuration and driven by a sinusoidal excitation voltage at30kHz. Comprehensive electrical and optical diagnostics and High-speed photography diagnosis are carried out on this discharge plasma jet. Electron excitation temperature is estimated by using Boltzmann’s plot method. Moreover, the characteristic spectral lines587.6nm,706.5nm and728.lnm of helium atoms are chosen to determine the excitation temperature under a Boltzmann approximation. The gas temperature in discharge tube is also estimated. In addition, the temperature of plasma effluent (plasma jet outside of the quartz tube) is observed by using fiber optic temperature sensor (FOT-L-SD). We find that the gas temperature in the tube is higher than outside under the same experiment condition. Furthermore, it has been found that the intensity of the oxygen free radicals increase with the applied voltage. For the high-speed photography diagnostics, observing the derivation process of the jet through the ultra-high speed ns ICCD (PCO HSFC) cameras. |
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