Investigating the Characteristics of a Coplanar-Coaxial Atmospheric Pressure Dielectric Barrier Discharge Jet in Argon.

Non-thermal atmospheric pressure plasma jet can easily be generated via a coplanar-coaxial dielectric (quartz tube) barrier discharge configuration driven by AC high voltage source at 11 kHz frequency in flowing argon gas. The plasma jet was characterized by its physical dimension, electrical and optical emission properties. It was found that smaller diameter of the quartz tube produced jets of shorter length. To generate a jet at maximum length for larger tube diameters, higher gas flow rate was required. Increasing the width of the active electrode also produced plasma jets of longer length. Current spikes superposed on the sinusoidal current waveforms were observed when the active electrode of shorter length was used. These spikes diminished when the width of the active electrode was increased to 15 mm. When the active and ground electrodes were inter-changed in position, no plasma jet was formed externally but upstreaming of the jet was observed. No discharge was ignited when the ground electrode was removed. The spectrum obtained showed emission lines from the second positive system, C³Π_u - B³Π_g of molecular nitrogen as well as Ar I state. [ABSTRACT FROM AUTHOR]