Extending the volume and processing area of atmospheric pressure plasma jets

Atmospheric pressure plasmas have certain advantage in materials synthesis and processing that are not available with other approaches including low-pressure plasmas. In particular, the breadth of reactions afforded by non-equilibrium, low temperature plasmas is unique; plasmas produced in full density air allows one to extend the application space to systems and materials that are not vacuum compatible. Non-equilibrium, atmospheric pressure plasma jet devices are well-suited for such applications given their relatively simple design and modest power requirements. However, their size tends to limit their utility to small scale processes and treatments. In this work, we describe approaches to extend the volume of non-equilibrium, atmospheric pressure plasma jets and thus, surface area that can be treated. In particular, we consider geometric and gas flow solutions to increase volume. We use high-speed cameras, optical emission spectroscopy (OES), current and voltage measurements, and simulations to characterize the results and understand the potential for and/or limitations to scale-up. This work is supported by the Naval Research Laboratory base program.