Effect of pulse width on the production of radicals and excited species in a pulsed positive corona discharge

The effect of pulse width on the production of various radicals and excited species (OH, O, O3, N2(C 3Πu), N2+(B 2Σu+), OH(A 2Σ), O2(v)) in a pulsed positive corona discharge is measured. The densities of these species are measured using laser-induced fluorescence, light absorption and optical emission spectroscopy. It is shown that the pulsed corona discharge can be divided into three phases related to the production of radicals and excited species: (i) primary streamer, (ii) earlier part of secondary streamer and (iii) later part of secondary streamer. It is shown that phase (iii) is inefficient for the production of most of the radicals and excited species. Therefore, a short pulse is desirable for efficient production of radicals and excited species to cut off the inefficient later part of the secondary streamer. (paper)