Characterization of thermodynamically non-equilibrium high-temperature oxygen plasma downstream region

The higher reactivity and density of thermodynamically non-equilibrium high-temperature plasmas than that of glow-discharge plasmas are confirmed by the observation of atomic oxygen concentration and the population densities of the O(3P), O(1D), and O(1S) energy states. At 60 cm from the plasma exit, the downstream flow mainly consisted of the O(1D) state. This flow is about 95% O(1D) at 1000 W and the fraction of O(1D) state slightly decreases with increasing power due to the production of O+ ions. The flow is about 55% 0(1D) for 200-W glow-discharge plasmas, which also give a low atomic oxygen concentration.<lz>