Effects of Polarity on Interactions of Surface Ionization Waves

Atmospheric Pressure Plasma Jets (APPJs) are versatile tools for surface modifications, biomedical treatments, material fabrication, and pollution control due to their ability to produce chemically active species at near-to room temperatures. Applications can involve arrays of APPJs, resulting in interactions of surface ionization waves (SIWs) that offer opportunities to tune the plasma properties and, hence, the plasma chemistry and surface treatments [1-3]. We report the interactions of SIWs created on an ITO coated glass surface by two identical APPJs operated at different polarities. Each jet is operated with 1 slm helium gas and is powered by either a positive or negative 3 kV 200 ns DC pulse at 5 kHz repetition rate [4]. High-speed imaging reveals the temporal evolution of the interactions of the SIWs and Schlieren imaging captures the neutral gas dynamics. The temporally synchronized APPJs produce a visually distinct interaction zone. SIWs of the same polarity are shown to repel each other while SIWs of opposite polarity are shown to combine, leading to a rise in conduction current. A differentially pumped RGA is used to monitor the production of reactive species near the interaction region. The ability to control the conversion efficiency of CO₂ added to the feed gas by altering the polarity and distance between the jets is investigated.

[1] Douat, Claire, et al. Plasma Sources Science and Technology 21.3 (2012): 034010.

[2] Johnson, Michael J., et al. Journal of Vacuum Science & Technology B 42.3 (2024).

[3] Naidis, G. V. Plasma Sources Science and Technology 21.3 (2012): 034003.

[4] Bentz, Brian Z. Plasma Sources Science and Technology 32.10 (2023): 105003.