Laplacian approximation of Warburg distribution

Negative pin-to-plane corona is studied and a Warburg-like planar current density distribution is derived in an electrostatic approximation of a point charge model. The derivations are assessed against experimental and theoretical studies available in the literature. A variation of corona current with the inverse of the square of the gap distance following from our model is also experimentally confirmed. Our modeling may also be useful in assessing major trends in analytically more difficult electrode configurations.