Microdischarge behaviour in the silent discharge of nitrogen - oxygen and water - air mixtures

Abstract

In this paper measurements of the behaviour of single microdischarges between metal and glass electrodes for both negative and positive polarities of the metal (designated and transitions, respectively), as well as the overall discharge behaviour between glass electrodes (GG), will be presented for different nitrogen - oxygen and water vapour - air mixtures. Increasing the oxygen concentration in nitrogen decreases the transferred charge per microdischarge for both polarities ( and ), while the total transferred charge per cycle is increased. With increasing water content in air, more charge is transferred per microdischarge for the polarity , but no significant change in the amount of transferred charge was found for a microdischarge. Less total charge is transferred per cycle with increasing water content. This is also true for double-dielectric barrier discharges (GG). The results suggest that water vapour coats the dielectric, reducing the surface resistance and increasing the effective dielectric capacity. This mechanism is supported by analysis of the voltage versus charge plot (Lissajous figure) for the involved capacitances of a double-barrier discharge. The reduction of the surface resistance of the dielectric and the resulting increase in the effective dielectric capacitance, are shown by photographs of spatially isolated microdischarges in a metal - pin dielectric arrangement.

Characteristics of dielectric barrier discharge reactor for material treatment

“…Experimentally, the charge Q is delivered from the voltage drop across a measuring serial capacitor of 0.91µF. The average electric energy W dissipated in a discharge cycle is then simply the area of the characteristic Lissajous figure, which in most cases is nearly a parallelogram [11]. Then the mean discharge power is calculated according to the relation P=f W. Figure 3 shows waveforms of the voltage applied to the reactor and the associated discharge current at 2.0mm reactor gap.…”

Improved performance of non-thermal plasma reactor during decomposition of trichloroethylene: Optimization of the reactor geometry and introduction of catalytic electrode

“…where V b is the effective gas breakdown voltage, C diel the capacitance of the dielectric and C gas is the capacitance of the gas, the discharge reactor is purely capacitive [27]. The voltage across the discharge gap (V gas ) is not high enough to ignite a plasma.…”

Atmospheric-pressure diffuse dielectric barrier discharges in Ar/O2gas mixture using 200 kHz/13.56 MHz dual frequency excitation

“…Hence there is only a displacement current, and the slope dQ/ dV corresponds to the total reactor capacitance. Lines AB and CD represent the phase when the plasma is formed in the gas gap, and the slope of these lines can approximately indicate the total capacitance of the dielectrics [41]. The Lissajous figure of the RF discharge has approximately an oval shape since the RF plasma is in a continuous mode, and therefore the 'plasma-off' phase cannot be distinguished, see figure 3 The capacitances, the charge transferred through the gas gap per LF half cycle (Q trans ) and the averaged power (P) of the LF, RF and DF discharges are summarized in table 1.…”