Determining the streamer velocity in an atmospheric pressure plasma jet from the target substrate current

Abstract

Plasma jets are an atmospheric pressure plasma source that projects streamers outside the bounds of the plasma device. The electric field produced by these streamers can generate a current in the substrate before the streamer contacts the substrate. This displacement current is a strong function of the proximity of the streamer to the surface. We develop a basic model of the streamer traveling towards the substrate that can determine the streamer location and velocity from the measured displacement current. This simple approach shows good agreement with optical imaging equipment and can provide a means to rapidly quantify the streamer velocity.