Plasma excitation dependence on voltage slew rates in 10-200 Torr argon-nitrogen gas mixture DBD

An argon-nitrogen gas mixture dielectric barrier discharge (DBD) excited by fast rise time (similar to 20 ns) and slow rise time (similar to 100 ns) 3-5 kV high-voltage pulses was investigated in the pressure range 10-200 Torr. Time resolved emission intensities of Ar (2p(1)-1s(2)), Ar (2p(9)-1s(5)), N-2 (C-3 Pi(u)-B-3 Pi(g)) and N-2(+) (B-2 Sigma(+)(u)-X-2 Sigma(+)(g)) were recorded while the applied voltage was kept constant during measurements. The influence of different applied voltages and nitrogen concentrations on the observed emission spectra was also obtained. The reduced electric field, E/n, was derived from the ratio of the measured emission intensities by comparing excitation rates calculated using the BOLSIG+ code. The corresponding electron excitation energies, T-e(Ex), were obtained. For the fast-pulse excited DBD, T-e(Ex) was in the range 6-8 eV and it decreased by about 0.5 eV for the lower voltage slew rate excitation under the same experimental conditions. The ionization rates were also derived from the corresponding E/n. The pulsed DBD plasma processes with different voltage slew rates were analyzed based on the dependence of the observed emission spectra and T-e(Ex) on the discharge operating parameters. The discharge voltage, current and power deposition were also estimated from applied voltage and current measurements.