Single microdischarges in a barrier corona arrangement with an anodic metal pin: discharge characteristics in subsequent breakdowns

Abstract

Metal pin-to-dielectric-covered electrode arrangements can be considered as a combination of corona discharge and dielectric barrier discharge. In the current study, the discharge is operated in dry air at atmospheric pressure. Sinusoidal voltage is applied to the dielectric-covered hemispherical electrode, and the metal pin electrode is grounded. Using an ICCD camera and a current probe (Rogowski coil), images and current pulses of single microdischarges (MDs) are recorded simultaneously. In addition, a time-correlated single photon counting technique is used to record the spatio-temporally resolved development of the MDs. The appearance and properties of the MDs in the two polarities of the applied voltage differ significantly. In this contribution, only the results of the negative half-cycle, i.e. anodic pin, are presented. In this half-cycle, for the voltage amplitude being applied, two MDs appear in each applied voltage cycle. The first MDs leave a positive charge on the surface of the dielectric, which has considerable influence on the propagation and properties of the second MDs, namely slower propagation of the cathode directed streamer in the dielectric vicinity, further expansion of the plasma on the dielectric surface and longer presence of the bulk plasma in the gap.

About the Development and Dynamics of Microdischarges in Toluene-Containing Air

“…The experimental set-up is the same as described in [50] except the gas supply system. Figure 1 sketches the overall set-up.…”

“…Current pulse amplitude distributions are measured using "vertical histogram" option of the oscilloscope. The details of these measurements are described elsewhere [50].…”

“…The microdischarges are imaged by a lens, and recorded by an ICCD camera (Andor iStar). By setting the opening of the ICCD gate to different phases of the applied voltage, it is possible to take images of different discharge events within the high voltage cycle (see [50] for details). To measure the spatio-temporally resolved MD development, the light from the single DBD is guided to a monochromator (Princeton Instrument SP2300) entrance slit.…”

“…A highly sensitive photomultiplier for single photon counting (Hamamatsu H5773/Becker-Hickl PMC-100-04) is equipped at the exit slit of the monochromator. This photomultiplier is part of the multi-dimensional time-correlated single photon counting (TC-SPC, Becker-Hickl SPC 152) set-up [50]. The high-voltage-power source as well as the diagnostic devices are controlled by a trigger signal generated in the TC-SPC system in order to enable the recording of the MD development for different phases within the applied voltage cycle.…”

“…Recently, a metal pin-to-dielectric-covered electrode arrangement was investigated in dry air [50]. This electrode arrangement combines the main features of single-DBDs and corona discharges.…”