Jet-to-jet interactions in atmospheric-pressure plasma jet arrays for surface processing

Atmospheric Pressure Plasma Jet (APPJ) arrays are considered as one of the most promising methods for uniform plasma processing of large uneven surfaces. To improve the downstream uniformity and enhance the surface treatment effects, it is important to reveal the mechanisms of the jet-to-jet interactions of plasma plumes in the jet array. In this paper, the electrical, optical, and fluid characteristics of the He and Ar three-channel one-dimensional (1D) plasma jet arrays with cross-field needle-ring electrode structure are studied and compared. It is found that there are divergences in the outside plumes of the propagation trajectory by the repellency of the plasma bullets and the spatial uniformity of the He and Ar plasma jet arrays can be improved with a lower applied voltage and a higher gas flow rate. The deflection angle of side plumes with respect to the central one of He is larger than that of Ar jet array due to the lighter molecular weight and better discharge synchronization. The experimental results show that Ar jet array is more controllable and stable and is more suitable for the design of the practical, simpler, and cheaper scalable plasma jet arrays.