Numerical and experimental investigation of the effect of N2 and O2 admixtures in a helium dielectric barrier discharge

Low temperature atmospheric pressure plasma sources have received much attention in the last decades, due to low production cost, easy implementation and applications ranging from surface modification, sterilization, plasma medicine etc. Such plasma sources usually operate with inert gases such as argon, neon or helium, and their electrodes are covered with dielectric layers in order to avoid the transition to arcing. The inert gases are preferred because they create the conditions for lower power requirements and they can produce a wide range of reactive species. However, in several applications, extra admixtures of nitrogen or oxygen species are added in the gases, in order to enhance the production of the reactive species. In the literature, there is a very limited number of studies regarding the effect of these admixtures on the evolution of helium discharge over a wide range. Consequently, understanding the effect of these admixtures (nitrogen and oxygen) on the discharge evolution is very crucial for the utilization of helium atmospheric pressure plasma devices.