Electrical characterization of a constant-current mode DC powered atmospheric pressure argon gliding arc discharge

In this study, we investigate a constant-current mode DC powered argon gliding arc discharge (GAD) operating at atmospheric pressure. The evolution of the discharge is comprehensively illustrated using multi-resolution electrical signals. Moreover, the impact of discharge current (ID) and gas injection flowrate (Φ) on the discharge characteristics is explored through electrical signals, fast Fourier transform and fast camera images. We observed that, within one discharge period, the GAD initiates with a spark breakdown and rapidly transits to an abnormal glow discharge within approximately 1 µs. Subsequently, it evolves into a normal glow discharge over approximately 40 µs until the discharge extinguishes. Two distinct discharge operation modes are identified in the limits of our experimental window, periodic and quasi-continuous, as a function of ID, each exhibiting different responses to Φ. Analysis of current waveforms and fast camera images reveals that discharge extinction occurs due to the fast deionization process in the periodic discharge operation mode, while it results from the complex interplay between the discharge and gas flow in the quasi-continuous discharge operation mode. In the latter mode, the discharge power and the duty cycle are much higher than those observed for the periodic mode, which suggests potentially better performances for the quasi-continuous mode. Finally, several discharge parameters and plasma parameters are estimated for the normal glow discharge mode (ID = 50 mA and Φ = 10 slm). In this mode, the evaluated average electric field in the plasma column and discharge power (PD) are 4.5 kV m−1 and 39.9 W while the spatially-averaged gas temperature, electron temperature and electron density are approximately 521 ± 33 K, 1.35 eV (15 660 K), and 2.8-7.1 × 1014 cm−3, respectively.