The influence of O2 content on the spatio-temporal development of pulsed driven dielectric barrier discharges in O2/N2 gas mixtures

This paper presents experimental results on the spatio-temporal development and breakdown statistics of filamentary microdischarges (MD) in O-2/N-2 gas mixtures at atmospheric pressure. The influence of the O-2 admixture was studied for 0.1-20 vol% O-2 in N-2. Electrical measurements were recorded, as were simultaneous streak and iCCD images of MDs in a pulsed-driven barrier discharge of 1 mm gap. The O-2/N-2 percentage was found to have a significant impact on the electrical characteristics, the temporal development of the MDs and its breakdown statistics, e. g. an increase in the temporal jitter of breakdown occurrence. A higher O-2 concentration leads to a delay in ignition time, a shorter discharge duration, an increasing discharge radius, higher discharge current maxima, rising breakdown field strength values over the gap and larger velocities of the cathode directed streamers. These changes can be explained by the electronegativity and effective collisional quenching of O-2, in combination with the steep rise of the voltage pulse.