Characteristics of helium plasma jet driven by microsecond pulses with different configurations

Summary form only given. The configuration and characterization of plasma jet are essential for their various applications. In this paper, two different configurations are used as high electrode: single tungsten electrode and tungsten electrode covered with quartz tubing (inner tubing). The high electrode is inserted into the middle of quartz tubing (outside tubing). The effect of inner quartz tubing on electrical property was investigated. Furthermore, the plasma jet was analyzed by optical emission spectroscopy (OES) by changing the pulse repetition frequency and outside tubing diameter. The experimental results showed that with quartz tubing, the initial excitation voltage was increased but the current decreased. With a higher frequency, the discharge would be more intense but with a lower voltage tolerance ability. The plasma jet plume injected to air straightly in 5 mm quartz tubing, while the plume curled up in 10 mm quartz tubing. OES observed that the intensity of reactive species in plasma jet increased when higher frequency and larger quartz tubing diameter was used.