Study of atmospheric pressure air diffuse discharge based on plasma jet

Atmospheric-pressure air plasma draws extensive interest for its gas-free operation, portability and low cost across industrial, medical and environmental fields. However, such plasmas show contracted or divergent morphologies with mutually exclusive merits. Thus, producing stable spatially diffuse plasma jets in atmospheric air remains a technical challenge. This study introduces a novel slit-based electrode configuration with an insulating sandwich architecture and presents a control strategy that converts localized gap discharges into volumetric, spatially dispersed discharges. First, by shaping the electric field with the sandwich electrode, the bundled, contracted jet emitted from the tip of a single enamel-insulated needle converts into a conical, diffuse plasma jet. Second, by varying cathode position, voltage amplitude, insulation thickness, and slit width, control can be further achieved from the gap discharge mode to the spatial large-volume diffuse discharge mode. Third, by changing the wire diameter and adjusting the position of the anode, the dispersion range of the large-volume and diffuse discharge in space can be controlled. Finally, a layered electrode structure was designed, which enabled an arrayed dispersion plasma. This achieved efficient and uniform modification of the surface of wool fabric, significantly enhancing its surface wettability.