Experimental study of Q-V Lissajous figures in nanosecond-pulse surface discharges

A charge-voltage Lissajous figure is a standard method for the electrical diagnostics of DBD discharges. Based on a repetitive nanosecond-pulse generator, some experiments on surface discharges are carried out in open air. The effects of applied voltage amplitude, pulse repetition frequency, electrode gap spacing, and electrode width on the characteristics of the Lissajous figures are presented in this paper. Results show that two different kinds of typical discharge characteristics are observed, and the discharge characteristics vary between these two kinds of discharges when the discharge parameters change. The applied voltage has little effect on the shape of the Lissajous figure, and the total and barrier capacitances of actuator. Both transported charge and energy per pulse are proportional to the applied voltage amplitude. The applied voltage plays an important role in the discharge uniformity, intensity and length of surface plasmas. The pulse repetition frequency plays an important role in the energy and discharge intensity accumulation and has no effect the electrical parameters of surface discharges. The shape of the Lissajous figure gradually changes with the electrode gap and the transported charges proportionally decrease as the electrode gap increases. There is a transition gap spacing to obtain the maximum plasma energy and to achieve a relatively uniform plasma. The capacitances of the actuator, the transported charges and energy per pulse increase with the electrode width. The intensity of surface discharges is little affected by the electrode width, but the plasma uniformity tends to worsen with the increasing width. There is a corresponding relationship between the shape of the Lissajous figures and the uniformity of plasma distribution. The almond-like Lissajous figure is attained with a compromise between the electrode gap and width.