The dynamic evolution of atmospheric-pressure pulsed air discharge over a water droplet

In this paper, a pin-to-plate reactor with a water droplet as a suspended electrode is employed to investigate the dynamic evolution of pulsed air discharge over the water droplet. The temporal and spatial evolution of the pulsed discharge is captured by an intensified charge-coupled device (ICCD) camera, and the spatial distribution of the electric field is obtained by solving the Maxwell equations. Our ICCD measurements show that the discharge is initiated in the gas gap between the anode and the droplet, and then it propagates over the droplet. Our simulation confirms that the strong electric field is formed when the water droplet is placed in the gas space. The propagation of air discharge over the water droplet anode-directed and its propagation velocity is on the order of 1.8 × 105 m s−1. With a decrease in the applied voltage, the long duration of air discharge is formed in the gas space, which could be related to the diffusion-controlled combination of charges remaining in the water droplet.