Temporal evolution characteristics of an annular-mode gliding arc discharge in a vortex flow

An annular-mode gliding arc discharge powered by a 50Hz alternating current (ac) supply was studied in a vortex flow of dry and humid air. Its temporal evolution characteristics were investigated by electrical measurement, temporally resolved imaging, and temporally resolved optical emission spectroscopic measurements. Three discharge stages of arc-ignition, arc-gliding, and arc-extinction were clearly observed in each half-cycle of the discharge. During the arc-gliding stage, the intensity of light emission from the arc root at the cathode was remarkably higher than that at other areas. The spectral intensity of N-2(C-3 Pi(u)-B-3 Pi(g)) during the arc-ignition stage was much higher than that during the arc-gliding stage, which was contrary to the temporal evolutions of spectral intensities for N-2(+)(B-2 Sigma(+)(u) - X-2 Sigma(+)(g)) and OH(A(2)Sigma(+) - X-2 Pi(i)). Temporally resolved vibrational and rotational temperatures of N2 were also presented and decreased with increasing the water vapor content. (C) 2014 AIP Publishing LLC.