A Pulsing Argon Plasma Plume Excited by a Direct-Current Voltage

In this study, by using a plasma jet driven by a direct-current voltage, a plasma plume can be generated in ambient air with argon used as the working gas. Through optical and electrical measurements, it is found that the plume discharge is pulsed despite the application of a direct-current voltage. The pulse frequency is investigated as a function of the sustaining voltage across the two electrodes and the gas flow rate. Differently from those of ordinary jets that usually operate in the bullet or continuous mode, the discharges of the direct-current jet almost volley at the same moment, while the quenching of the discharges propagates away from the jet nozzle.