Effect of oxygen concentration on the postdischarge decay of hydroxyl density in humid nitrogen-oxygen pulsed streamer discharge

In this study, the effect of oxygen (O2) concentration in the range of 0.000 1% (= 1 ppm) to 20% on the decay of hydroxyl (OH) density after pulsed streamer discharge is examined in a humid nitrogen-oxygen mixture under atmospheric pressure. The decay of OH density was measured using laser-induced fluorescence and compared with one-dimensional postdischarge simulations. The simulation results are consistent with the measured decay of OH density for all O2 concentrations. Essentially, the OH decay was double exponential, consisting of initial rapid decay for t 1 ms, where t represents the postdischarge time. In the slow decay phase, O2 change in the order of 10 ppm markedly affected the OH decay rate when O2