Primary and Secondary Streamer Dynamics in Pulsed Positive Corona Discharges

Preliminary comparisons between numerical simulation and experimental results are obtained under pulsed applied voltages in the case of positive point to plane corona discharges in dry air at atmospheric pressure. The experimental conditions correspond to 7 mm interelectrode distances with a tip radius of 20 $\mu\hbox{m}$. The calculations are based on a first-order 2-D electrohydrodynamic model including the main charged-particle/gas reactions occurring in dry air discharge. The development of the corona discharge is analyzed using streak camera pictures. The transition from the branching structure to the monofilamentary one is described. An interesting comparison is performed between the streak camera pictures and the spatiotemporal evolution of the calculated ionization rate. This shows a qualitative agreement in the development of both primary and secondary streamers.