Recent advances in modeling low-temperature kHz atmospheric pressure plasma jets and their interactions with surfaces

Typically, in an atmospheric pressure plasma jet, a discharge is ignited in a noble gas (helium being the most used) flowing in a tube and the jet expands into air before impacting a target.  Many studies have shown that plasma jets can generate high fluxes of reactive species at low gas  temperatures.  Consequently,  their  use  has  been  investigated  for different applications  as  living  tissue  treatment,  polymer  etching,  water  treatment  and  food decontamination.

In the literature, there is a large diversity of set-ups for plasma jets with different electrode geometries, various admixtures in the noble gas used, different tube geometries, flow  rates  and distances between the  plasma generation  and  the target. The use of pulsed kHz sources of positive or negative polarities has allowed more detailed measurements of discharge properties and comparisons with fluid simulations. It was found that the ionisation waves in jets are very similar to air streamers, although guided by the buffer gas channel, and are typically referred to as guided streamers. Therefore, the study of plasma jets is also from the fundamental point of view a very unique opportunity to better understand streamer physics from its ignition to its interaction with different surfaces (floating dielectric and metallic and grounded metallic).

 In this talk, we focus on recent advances in the fluid modeling of plasma jets and their comparisons with experiments on the distribution in space and in time of reduced electric field, mean electron energy and electron density. These quantities allow a better understanding of the discharge dynamics and are also the key quantities that drive the production of active species of interest for plasma jet applications.