The role of associative ionization reactions in the memory effect of atmospheric pressure Townsend discharges in N ₂ with a small O ₂ addition

In this work, we investigate the role played by associative ionization reactions in the memory effect of atmospheric pressure Townsend dielectric barrier discharges working in N 2 with a small addition of O 2 . Systematic laser-induced fluorescence measurements are carried out in order to provide the absolute densities of N and O atoms and NO molecules for different oxygen concentrations. The use of these data in a dedicated model allows us, in particular, to estimate the rate of the reaction N( 2 P)+O( 3 P) → NO + + e suspected of playing a significant role. According to the obtained results, this reaction is found responsible for a significant enhancement in the production of seed electrons between two successive discharges at 25 ppm of O 2 , in good agreement with experimental observations. It confirms the importance of this associative ionization reaction in these experimental conditions.