Space and time resolved characterization of a RF atmospheric pressure plasma jet by E-FISH measurements and PIC/MCC simulations

The so-called COST-jet [1] is a standardized RF driven atmospheric pressure plasma source that allows to accumulate a large wealth of experimental data on various radicals and excited species. To the best of our knowledge, no model independent data exist on the time and space resolved electric field and charge densities in this jet. In this work we report for the first time experimental measurements of these basic plasma parameters in a He-N₂ fed COST-jet-like discharge that easily allows application of Electric Field Induced Second Harmonic generation (E-FISH) to measure the electric field [2]. Experimentally determined electric fields allow for a first principle derivation of the discharge voltage, the total current density, the space and time varying electron density and the period-averaged spatial distribution of the ion density. The results are in excellent agreement with those obtained by PIC/MCC simulations. Both, experiment and simulation, confirm a recent theory on the non-quasi neutrality of the RF-APPJ discharge [3].

[1] Golda, J. et al, JPhysD, 49, 084003 (2016).

[2] Orel, I. et al, PSST, under review.

[3] Klich, M. et al, PSST, 31, 045003 (2022).