Formation of discharge plasma on the surface of cathodes with different dielectric constants

We present a detailed study of the spatial and temporal evolution of visible light emission from plasma formed on the surface of ferroelectrics [Pb(Zr,Ti)O-3 and BaTiO3] and a printed-circuit board under the application of a high-voltage pulse. For all samples studied, plasma formation occurs within the first 5 ns from the start of the high-voltage pulse. It is shown that the plasma appears at the edges of the front strip electrodes. Further, the plasma spreads along the dielectric surface covering it partially. It is found that the uniformity of the plasma and the distance of its propagation along the surface depend on the properties of the dielectric, the polarity and amplitude of the high-voltage pulse, and the vacuum conditions. A qualitative model which explains the observed experimental data is suggested. (C) 1999 American Institute of Physics. [S0021-8979(99)03211-9].