This paper deals with positive and negative corona discharge in atmospheric
air using a wire-to-plane system. The Poisson's equation is solved
numerically using the finite-element method and the current continuity
equation. The space charge density is updated using the simplified method of
characteristics, where the ion diffusion is neglected. The numerical model
takes into account the avalanche length of the corona discharge and the
potential corresponding to the minimum ionisation field is directly
introduced in the method on the border of the ionisation region.
The end geometry of the linear biased probe without wraparound bias plates
has been adapted to a wire-to-plane system for use in DC corona discharge.
The current density and the electric field are measured; their spatial
distributions are given and compared with the computed values. The agreement
between the calculated values and those obtained experimentally is
satisfactory. The per unit electric field and current density are also
represented by a unique function.