Effect of gas flow on transport of O ( super(3)P sub(j)) atoms produced in ac power excited non-equilibrium atmospheric-pressure O sub(2)/Ar plasma jet

The Spatial distribution of O ( super(3)P sub(j)) atoms emitted from a non-equilibrium atmospheric-pressure O sub(2)/Ar plasma jet in ambient N sub(2) gas has been measured by using the vacuum ultraviolet absorption spectroscopy. In remote regions of the plasma, the absolute density of O ( super(3)P sub(j)) atoms for a total gas flow rate of 1 slm decreased from 4.1 x 10 super(14) to 1.5 x 10 super(13) cm super(3) as the distance from the main discharge region increased from 10 to 16 mm and that for 5 slm decreased from 7.7 x 10 super(14) to 2.0 x 10 super(14) cm super(3). The reduction ratio thus changed from 0.037 to 0.259 with increasing total gas flow rate. Although loss of O ( super(3)P sub(j)) atoms occurs frequently due to the influence of N sub(2) or nitrogen oxide species produced by the inflow of ambient gas, it is found that the gas flow velocity is a very important factor for the transport of the active species to longer distances from the plasma, and it determines the material processing performance for a non-equilibrium atmospheric-pressure O sub(2)/Ar plasma jet.