Strong Correlation Effects in Atmospheric Pressure Plasmas*

Atmospheric pressure plasmas have been widely tested for numerous applications showing promising results and an increasing interest due to the reduced running cost and operational simplicity. In this work, we show that the ion species are strongly coupled in atmospheric pressure plasmas and this leads to strongly correlated effects that currently are not accounted for in standard modeling techniques. Using first principles Molecular Dynamics simulations, we observed that the ion temperature is set by Disorder Induced Heating (DIH), ion-neutral temperature relaxation through collisions and ion-neutral 3-body recombination. We show that the maximum and equilibrium ion temperatures increase with the ionization fraction and that effect can be correctly predicted using energy conservation arguments and accounting for the DIH. We also show that the ion-ion interactions are not screened by the presence of neutral atoms. The observed effects show that atmospheric pressure plasmas are sufficiently dense that they are influenced by strong correlation effects associated with many-body interactions that are not treated in the dilute limit.