Investigation of memory effect in atmospheric pressure dielectric barrier discharge in nitrogen with small oxygen or nitric oxide addition

This work focuses on the investigation of the memory effect origin in atmospheric pressure Townsend discharges in nitrogen/oxidizing gas mixtures. For this purpose, an experimental approach is used on a plane-to-plane dielectric barrier discharge, using short exposure time photographs of the discharge with interference filters, synchronized with the discharge current. A segmented electrode into eight strips allows to correlate the discharge current and light emissions from different species in time and space (position along the gas flow). The results highlight the occurence of a memory effect involving oxidizing species when an oxidizing gas is added to nitrogen. A comparison of the discharge for different gas gaps, and the parallel drawn with a numerical 1-D model in pure nitrogen, suggests the importance and the predominance of this memory effect compared to the secondary electron emission by N-2(A(3)Sigma(+)(u)) which was considered to be the dominant mechanism up to now.