Effects of surface microstructure on atmospheric-air repetitive single-filament DBD

Surface microstructure is an effective approach for modulating dielectric barrier discharges (DBDs). In this study, a two-dimensional (2D) plasma fluid model is employed to investigate the influence of micron-scale surface structures (0-50 μm) on a single-filament atmospheric-pressure air DBD driven by a sinusoidal voltage, with a focus on volume and surface streamer dynamics. The results show that larger microstructures can lead to discharge timing delay or advancement, current waveform distortion, and streamer morphology modification. For the studied sinusoidal profiles, surface streamer splitting can be induced by a microstructure size (peak-to-peak amplitude) as small as 25 μm, whereas noticeable changes in volume streamer parameters require a larger size (e.g., 50 μm). Furthermore, the discharge exhibits asymmetry between consecutive positive and negative half-cycles due to the memory effect, and the influence of microstructure differs distinctly with voltage polarity. The local electric field distortion, the residual ion density and seed electron level, and the distribution of surface charges are identified as key factors through which microstructures govern the discharge behaviors. This work provides new insights into the active control of DBDs via surface microstructures.