Numerical modelling of positive surface streamer in air

The development of a positive surface streamer in air at atmospheric pressure is numerically modelled by solving the coupled continuity and Poisson´s equations. The geometry includes a 100 ¿m radius of curvature needle setting perpendicular to a 1 mm thick insulator. The continuity equations are accurately solved for using the 1-D finite-volume flux-corrected-transport (FV-FCT) algorithm while Poisson´s equation is analysed using a simplified version of the disc method. Results obtained show the propagation of the streamer with time and distance together with the distributions of electrons, positive and negative ions. The computed streamer velocity and propagation length are in good agreement with the experimental data.