Spatially Resolved N2（A3Σ＋u, ν=0） Decay Studies in the Pulsed Direct-Current Nitrogen Discharge using the Laser-Induced-Fluorescence Technique

We focus on the investigation of the spatial distribution and temporal evolution of N2（A3Σ＋u, ν=0） in a very early afterglow of a pulsed dc nitrogen discharge. The results indicate that a fast quenching process of N2（A3Σ＋u, ν=0） exists in the very early afterglow. We study the dependence of this fast quenching process on the discharge pressure 20–40 torr. It seems that this fast quenching behavior of N2（A3Σ＋u, ν=0） found in our experiment can be ascribed to the combined action of pooling reaction and collisions with N atoms through N2（A3Σ＋u）＋N2（A3Σ＋u）→ N2＊＋N2（N2＊=N2（B3Πg, C3Πu, C＇3Πu, C＂5Πu）） and N2（A3Σ＋u）＋N（4S）→N（2P）＋N2, respectively. Meanwhile, the decay studies of N2（A3Σ＋u, ν=0） near the anode and cathode infer that the production of N（4S） atoms does not distribute uniformly along the axis of the discharge gap at relatively low pressure, and this effect becomes gradually inconspicuous with the increasing discharge pressure.