Volume added surface barrier discharge plasma excited by bipolar nanosecond pulse power in atmospheric air: optical emission spectra influenced by gap distance

摘要

In this paper, volume barrier discharge with different gap distances is added on the discharge border of high-voltage electrode of annular surface barrier discharge for generating volume added surface barrier discharge (V-SBD) excited by bipolar nanosecond high-voltage pulse power in atmospheric air. The excited V-SBDs consist of surface barrier discharge (d = 0 mm) and volume added surface barrier discharges (d = 2 mm and 3 mm). The optical emission spectra are recorded for calculating emission intensities of N-2 (C-3 Pi(u) - B-3 Pi(g)) and N-2(+) (B-2 Sigma(u)(+) - X-2 Sigma(+)(g)), and simulating rotational and vibrational temperatures. The influences of gap distance of V-SBD on emission intensity and plasma temperature are also investigated and analyzed. The results show that d = 0 mm structure can excite the largest emission intensity of N-2 (C-3 Pi(u) - B-3 Pi(g)), while the existence of volume barrier discharge can delay the occurrence of the peak value of the emission intensity ratio of N-2(+) (B-2 Sigma(+)(u) - X-2 Sigma(+)(g))/N-2 (C-3 Pi(u) - B-3 Pi(g))during the rising period of the applied voltage pulse and weaken it during the end period. The increasing factor of emission intensity is effected by the pulse repetition rate. The d = 3 mm structure has the highest threshold voltage while it can maintain more emission intensity of N2 (C-3 Pi(u) - B-3 Pi(g)) than that of d = 2 mm structure. The structure of d = 2 mm can maintain more increasing factor than that of the d = 3 mm structure with varying pulse repetition rate. Besides, the rotational temperatures of three V-SBD structures are slightly affected when the gap distance and pulse repetition rate vary. The vibrational temperatures have decaying tendencies of all three structures with the increasing pulse repetition rate.