Search

The pseudoglow and glow discharge behavior of a 0.5-mm metallic-dielectric electrode gap in helium under atmospheric pressure was examined as a function of ac voltage between 0.3 and 32 kHz. The number of discharge current pulses per half-cycle within the pseudoglow was found to diminish with rising frequency, as opposed to the increase observed with rising voltage. The reduction in the rise time and the quasi-monotonic decreases in amplitude of the successive discrete current pulses within the pseudoglow were attributed to the enhanced Penning ionization due to an increase in the number of energetic precursors (metastables and dimers) over the first quadrant in each half cycle. The interruption in the discharge pulse sequence, caused by a change in polarity of the ac field, greatly reduced the precursors' concentration and resulted in the first incipient pulse of the pseudoglow having the shortest rise time and width in the pulse sequence. The increase in frequency at constant voltage caused a gradual decrease in the number of discharge current pulses within the pseudoglow, until at ca. 10 kHz and beyond only a single pulse glow discharge took place. The influence of argon, nitrogen, hydrogen, and oxygen impurities was studied and interpreted in terms of Penning ionization and electron attachment. [ABSTRACT FROM AUTHOR]

Presents a study that examined the influence of surface charges upon the partial discharge behavior of a short metallic-dielectric plane-parallel electrode gap in an air-like mixture at atmospheric pressure. Form of charge distribution at the dielectric electrode surface; Application of a simulation model; Results and discussion.

Two dielectric barrier discharge (DBD) reactors, one small, the other about 40 times larger, associated equipment, and a dedicated MATLAB code have been used to carry out precise determinations of electrical energy, $E_{g}$ , dissipated per discharge cycle of the applied a.c. voltage, $V_{a}$. In the smaller reactor, this was done over the frequency range $5 \le f\le 50$ kHz and using twin pairs of several different insulating materials (2.54-cm-diameter disks) with relative permittivities between $2.1 \le \kappa _{\text {die}}^{\prime }\le 9.5$ as dielectric barriers in DBDs for four different gases: He, Ne, Ar, and N2. In the large reactor, $f$ was restricted to 20 kHz in Ar and He; this latter system primarily serves for plasma polymerization experiments in which organic “monomers” are admixed with the flow of Ar as carrier gas. We report the method for exactly evaluating $E_{g}$ , and then present and compare values measured under different conditions. To the extent possible, these are compared between the small and large reactors, and with results published in the literature. The reliability of the method is confirmed, for example, by reproducing published breakdown fields of the gases examined, and by several other original results. [ABSTRACT FROM AUTHOR]

Presents a study that investigated the atmospheric pressure glow discharges in a dielectric barrier discharge rector. Background on scientific investigation of gas discharges at atmospheric pressure; Methodology; Examination of the discharges in different noble gases under varying experimental conditions.