Plasma diagnostics of atmospheric plasmas is a key tool in helping to understand processing performance issues. This paper presents an electrical, optical and thermographic imaging study of the PlasmaStream atmospheric plasma jet system. The system was found to exhibit three operating modes; one constricted/localized plasma and two extended volume plasmas. At low power and helium flows the plasma is localized at the electrodes and has the electrical properties of a corona/filamentary discharge with electrical chaotic temporal structure. With increasing discharge power and helium flow the plasma expands into the volume of the tube, becoming regular and homogeneous in appearance. Emission spectra show evidence of atomic oxygen, nitric oxide and the hydroxyl radical production. Plasma activated gas temperature deduced from the rotational temperature of nitrogen molecules was found to be of order of 400 K: whereas thermographic imaging of the quartz tube yielded surface temperatures between 319 and 347 K.
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机译:大气等离子体的等离子体诊断是帮助理解加工性能问题的关键工具。本文介绍了PlasmaStream大气等离子体喷射系统的电学,光学和热成像成像研究。发现该系统表现出三种操作模式;一个收缩/局部血浆和两个扩展体积的血浆。在低功率和氦气流下,等离子体位于电极上,并具有电晕/丝状放电的电特性,具有电混沌的时间结构。随着放电功率和氦气流量的增加,等离子膨胀到管的体积中,外观变得规则且均匀。发射光谱显示出原子氧,一氧化氮和羟基自由基产生的证据。由氮分子的旋转温度推导出的等离子体活化气体温度约为400 K:而石英管的热成像成像得出的表面温度为319至347 K.
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