Development and morphological characterization of ion wind in an inhomogeneous DC field

Ion wind is a concomitant phenomenon arising from the process of discharge development, and is widely used in heat dissipation and ion neutralisation. The morphology characterization of ion wind was observed using a photo-electric joint monitoring system consisting of a photomultiplier tube(PMT), a Rogowski coil, and Schlieren apparatus. According to the morphological and photo-electric characteristics, the development of ion wind could be divided into three stages, including an intermittent ion wind, a stable ion wind channel, and a fluctuating ion wind channel. During intermittent ionic wind, the ion wind presented intermittent jet behaviours, and the time-delay between photo-current and grounding current was obvious. During the stable ion wind channel period, a columnar channel was formed, and there was no time-delay between photo-current and grounding current. During fluctuation in ionic wind, the current increased and the channel width fluctuated. The width of, and wind speed in, the channel with different gap spacings were analysed. A simplified model was established to simulate the formation of the ion wind under negative voltage. The simulation result showed that the concentration distribution of negative particles is similar to the channel morphology, and the ion wind is the track of neutral molecular migration driven by the movement of negative particles. Comparing the simulation and experimental results, the relationship between the motion state of charged particles, the charge density and the morphology of ion wind was analyzed.