Coplanar ac discharges between cylindrical electrodes with a nanoporous alumina dielectric: Modular dielectric barrier plasma devices

Dielectric barrier discharges between coplanar Al rods having an /spl sim/2-/spl mu/m-thick layer of nanoporous alumina dielectric at the surface have been investigated. Rods 3 mm in diameter, 7 cm in length, and spaced by 5 mm produce stable and intense glow discharges in 50 torr of Ne when pairs of rods are driven by an alternating current (bipolar) waveform for which the peak voltage is /spl sim/460-510 V.

Dielectric barrier discharges have long been of interest for applications such as lighting and broad-area ultraviolet (UV) generation, primarily because the design of devices is conceptually straightforward and the physics of the discharge lends itself to scaling of the effective emitting area [1]. The reliability and luminosity of the discharge are, in large measure, dependent upon the electrical characteristics of the dielectric, and economic factors continue to demand increased overall efficiency while reducing manufacturing costs. Modularity is also a critical consideration and wire electrodes are of particular interest for dielectric barrier plasma devices since they can be viewed as building blocks with which a virtually limitless range of geometric patterns and structures can be realized. Unfortunately, fabricating dielectric barrier electrodes from metal rods having a small radius of curvature is challenging, generally because of poor dielectric adhesion as a result of mechanical stress at the metal-dielectric interface.