Electrical breakdown and I-V characteristics of a hollow electrode radio frequency atmospheric pressure glow discharge of linear shape

Summary form only given. Open-air atmospheric pressure glow discharges offer the advantage of the not requiring a conventional vacuum chamber, thus making them a lower cost prospect for some materials processing applications. We flow rare gases He and Ar through linear electrodes to achieve stable open-air linear discharge. Our atmospheric discharge is composed of two parts: an active discharge between microelectrodes and a downstream afterglow plasma plume which exits from grounded slots. Our grounded electrodes are slots 7.5 cm long with a slot width of 200 microns. Opposing the grounded slots is a powered wedge-shaped electrode placed 400-600 microns away. Corona breakdown of the feed gas initiates the discharge. Once the discharge is ignited it is diffuse and uniformly occupies the entire length of the slot electrode. The afterglow plasma plume extends 1-6 mm from the grounded electrodes towards the surfaces of substrates. We present measurements of the RF electrical properties of an open-air slot shaped atmospheric plasma operating with He and Ar flows including: discharge voltage, discharge current, plasma impedance and plasma power consumption. In this data set we limit RF current densities to 0.11A/cm/sup 2/. Based on changes in capacitive impedance with RF current additional calculations have been made to roughly estimate the changing sheath distance as well as, sheath voltage, the electron temperature and the electron density. We demonstrate how these measurements and associated crude calculations help elucidate the physics of both the active microdischarge and the plasma plume.