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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]

Negative discharge induction experiments were performed with a rod-to-rod electrode configuration having a gap length of 0.8 m using a high-power XeCl excimer laser of maximum output energy of 2 J/pulse and an impulse generator of maximum voltage of 1.2 MV. Development of a leader in the laser-ionized plasma channel was observed by using an image converter camera. When a XeCl excimer laser is applied at a carefully controlled instant, the guiding effect for an impulse discharge is optimized. Three main results were obtained. First, the discharge started near the focal point and then developed bidirectionally toward the high-voltage electrode and the grounded electrode. Midgap leaders were frequently observed. Second, it was observed that the lifetime of the laser-ionized plasma channel was about 1 Ps. Third, the discharge processes were classified into six stages. The mechanism of the streamer and leader propagation is discussed. [ABSTRACT FROM AUTHOR]

This paper reports an experimental study of the optical emission characteristics of the surface dielectric barrier discharge plasma excited by nanosecond pulsed voltage. N2(C3Пu) rotational and vibrational temperatures are almost the same with upper electrode powered with positive polarity and lower electrode grounded or upper electrode grounded and lower electrode powered with positive polarity. While the electron temperature is 12% higher with upper electrode powered with positive polarity and lower electrode grounded. When the frequency is below 2000 Hz, there is almost no influence of applied voltage amplitude and frequency on N2(C3Пu) rotational, vibrational temperature and electron temperature. As the pressure decreases from 760 Torr to 5 Torr, N2(C3Пu) rotational temperature remains almost unchanged, while its vibrational temperature decreases initially and then increases. The discharge mode changes from a filamentary type to a glow type around 80 Torr. In the filamentary mode, the electron temperature remains almost unchanged. In the glow mode, the electron temperature increases while the pressure decreases. [ABSTRACT FROM AUTHOR]