Interelectrode gap filling with plasma in a sliding submicrosecond multichannel discharge of opposite polarities in rare gases.

The results from an experimental measurement of the interelectrode gap filling with plasma channels in a pulsed sliding multichannel discharge of opposite polarities in Ne, Ar and Xe are presented and discussed. The experiments are performed at submicrosecond pulse duration (50-800 ns current pulse FWHM) and gas pressures of 30 and 100 kPa, with two discharge cavities of different alumina ceramic substrate thicknesses (0.4 and 0.17 cm) and interelectrode gap lengths (4 and 10.3cm).A comparative measurement at opposite polarities is aimed at getting additional information on the discharge formation mechanism and optimal mode for quasi-uniform plasma sheet generation. The discharge features common for the three gases are revealed. In particular, the index of interelectrode gap filling with plasma channels is shown to depend at each gas type/pressure/cavity on the peak current, along with the discharge voltage, in such a manner that the greater the peak current at a fixed discharge voltage, the greater the gap filling index, independent of the voltage polarity. For the practical purpose of generating a quasi-uniform discharge structure, the lower of the two gas pressures, the positive discharge polarity and the lowest impedance of the power supply chain are preferable. [ABSTRACT FROM AUTHOR]