Experimental investigation of single microdischarges in a barrier corona arrangement with a cathodic metal pin

Abstract

Microdischarges (MDs) in a sinusoidally driven barrier corona discharge, operated in dry air at atmospheric pressure, are investigated using time-correlated single photon counting (TC-SPC) technique, electrical measurements (applied voltage and current pulses) and ICCD images. In the current contribution, results of the cathodic pin half-cycle are presented. Results of the anodic pin half-cycle were presented in a previous study (Jahanbakhsh et al 2018 Plasma Sources Sci. Technol. 27 115011). In the cathodic pin half-cycle appearance phase and current pulse amplitude of the MDs have an erratic behavior. Hence, a statistical study of the current pulse amplitudes is conducted, and it is correlated to the phase-resolved spatio-temporal development of the MDs, obtained from TC-SPC recordings. This study indicates that the breakdown and development of the MDs is dependent on their inception phase, which is related to the discharge activity in preceding (anodic pin) half-cycles. It is shown that the MDs appearing at lower applied voltages are ignited with a positive streamer starting near the anode (dielectric), similar to single dielectric barrier discharge MDs. On the other hand, the inception of the MDs appearing at higher applied voltages takes place with a double-streamer mechanism starting near the tip of the cathode (pin). These MDs have similarities to transient sparks, in particular much higher current pulse amplitudes compared to single DBDs.