Absolute and relative density measurements in a N2/Ar dielectric barrier discharge by diode-laser absorption spectroscopy and resolved plasma emission -: art. no. 103301

The population density of metastable Ar 4s'[1/2]degrees in a 70% Ar/ 30% N-2, short-pulsed (< 15-ns full width at half maximum) dielectric barrier discharge was determined from the time-resolved diode-laser absorption as a function of pulse repetition rate for a gas pressure of 100 Tort. The relative population density change of N-2(+) B (2)Sigma(u)(+) and N-2 C (3)Pi(u) was also determined from N-2(+) first negative and N2 second positive plasma emission for the same pulse repetition rates and pressure. The net power deposited per pulse was obtained from measurements of the voltage and current wave forms. The fractional energy dissipated in metastable Ar production was estimated from the power and absorption number density measurements to be roughly 20% for pulse repetition rates <= 10 kHz, decreasing to similar to 10% at 30 kHz for 3.5-kV applied voltage and 100 Torr. (c) 2005 American Institute of Physics.