Interaction between atmospheric pressure plasma jet and target

Abstract

Interactions of floating potential on metal and dielectric targets with He atmospheric pressure plasma jet (APPJ) were studied in this paper. The APPJ is generated in a needle-ring corona-dielectric barrier discharge configuration, driven by a sinusoidal voltage. The characteristics of APPJ were assessed through electrical and optical examinations, and the time-average electrostatic voltage on the targets was measured using both contact and non-contact electrostatic voltmeters. It was found that both metal and dielectric targets can promote the jet development and speed up the jet velocity. During the negative half-cycle, the “plasma cluster” propagates from the target toward the ground electrode and then “merges” with the forward plasma jet, leading to a reversed development of jet. The two targets follow a similar pattern on the surface electrostatic voltage, that is, initially in a positive polarity whose amplitude first increases and then decreases and transits to negative polarity with an increase in the applied voltage. But there are also some minor differences between the two targets, e.g., the metallic target can change the discharge pattern and reduces the discharge current under certain conditions.