Uniformity improvement of plumes in an atmospheric pressure argon plasma jet array by electric field optimization

Atmospheric Pressure Plasma Jet (APPJ) array is a promising way for producing plasma to process large-scale uneven surface. In this paper, the uniformity of a one-dimensional (1D) Ar APPJ array (three tubes with needle-ring electrode structure) driven by a nanosecond pulse power source is optimized through varying the distance between the tip of middle HV electrode and outside electrode, d. The effects of parameters (gas flow rate and applied voltage) on the uniformity of jet array are also investigated. The voltage-current waveform, discharge optical image and ICCD photograph are measured to reveal the jet-to-jet interactions. The results show that when d = 0 mm, the middle tube plasma jet length is always shorter than outsides, while all jets are ignited with almost equal length at d = 2 mm and the middle tube plasma jet length is longer than outsides at d = 4 mm. Thus, the uniform atmospheric pressure plasma jet array is obtained by setting d = 2 mm. The unconformity of the plasma jet array length is mainly attributed to the number of transferred charge of primary discharge. The results reported in our study would be able to promote the application of uniform jet arrays for various applications.