Study on the conditions to obtain a diffuse nanosecond positive ionization wave in a point-to-plane geometry in atmospheric pressure air

Recently, attention has been attracted to 2D axisymmetric diffuse positive discharges with radii of several millimeters produced by high overvoltages applied with nanosecond voltage fronts on point-to-plane geometries. In addition, to better understand the physics of these discharges, different diagnostics have been used to measure the time evolution of the electric field in several locations in the gap.

In this work, we use a 2D axisymmetric drift-diffusion fluid model to study how the shape of the high voltage electrode, its tip radius, the voltage rise time and the maximum applied voltage influence the dynamics and characteristics of the positive ionization wave propagating between the point electrode and the grounded plane. Based on this extended parametric study, we identify conditions to obtain diffuse nanosecond positive ionization waves in atmospheric pressure air.