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.