LAUSR

This paper presents a numerical study of the impact of the needle tip radius on the electrical characteristics of Trichel pulses in negative corona discharges for a needle-plane configuration in atmospheric air. The radius of curvature of the needle tip varies from 20 μm to 45 μm. The first current pulse, subsequent pulse train is discussed here based on the distributions of charged species and electric field. Three species continuity equations along with Poisson's equation are solved by the hydrodynamic drift-diffusion approach, in which the role of photoionization is considered. The increasing needle tip radius reduces the peak of the first pulse significantly and delays the start of the first pulse, but almost keeps the duration of the first pulse constant. At the instant of the first pulse peak, both the magnitude of the charged species densities and the electric field decrease with the needle tip radius, and the electric field is strongly distorted by the space charge field. For the subsequent curren...