Paper PS1-ThM5
Atmospheric Dielectric Barrier Glow Discharges at High Overvoltage

Thursday, October 23, 2008, 9:20 am, Room 304

Atmospheric dielectric barrier plasma glow discharges in pure nitrogen gas have been generated under overvoltage conditions produced with a custom high voltage source. A voltage rise time of 25 ns at 20-30kV is readily achieved by the source and is sufficient to create overvoltage conditions in excess of three times the DC breakdown voltage of nitrogen. These large overvoltage conditions occur because the rise-times required to achieve peak voltage are shorter than the lag time between the pulse crossing the threshold voltage and the onset of a discharge. Overvoltage conditions prior to discharge have been predicted to produce significantly higher average electron energies in the discharge and to produce high instantaneous power densities. Experimentally current densities have been achieved well in excess of 10 A/cm² for homogeneous glow discharges of pure nitrogen gas at atmospheric pressure with total pulse currents of 1 kiloamp having been obtained. The overvoltage potential on the electrodes enables manipulation of the reduced electric field, but additional control can also be garnered through increases in the gas temperature and/or decreases in the chamber pressure along with the applied overvoltage. This paper will emphasize the correlation between the overvoltage conditions, the dielectric material properties, temperature, and small deviations in pressure to the electrical charge transfer, optical properties, and propagation mechanisms of the glow discharge. This work was supported in part by ARL and AFRL.