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 visibl e 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 f ound 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 quali tative model which explains the observed experimental data is suggested. (C ) 1999 American Institute of Physics. [S0021-8979(99)03211-9].