Particle densities of the pulsed dielectric barrier discharges in nitrogen at atmospheric pressure

Pulsed dielectric barrier discharges (DBDs) have become a promising solution to generate atmospheric-pressure non-equilibrium plasmas. In this work, a one-dimensional fluid model is carried out to research particle densities of the pulsed nitrogen DBDs at atmospheric pressure. Averaged particle densities, time evolutions of axial distributions of particle densities and influences of discharge gap distance d_g on the particle densities are systematically illustrated and discussed. The calculation results show that averaged electron densities are lower than averaged N₂⁺ densities, but higher than other averaged ion densities. Time evolutions of axial distributions of electron, N⁺ and N₂⁺ densities show two peaks during rising and falling phases of applied voltage when d_g is 0.2 cm but present gradual increases during pulse width when d_g is 0.6 cm, which are similar to those of N₂(a′) and N₂(B). Maximums of N₃⁺ densities are close to the momentary cathode under d_g of 0.2 cm but locate near the grounded electrode under d_g of 0.6 cm, which are alike to those of N₂(A) and N₂(C). Besides, N₄⁺ densities nearby the momentary anode are higher than those nearby the momentary cathode when d_g is 0.2 cm. N(²D) has low averaged particle densities and complex time evolutions compared to N. (paper)