Simulation of corona at lightning‐triggering wire: Current, charge transfer, and the field‐reduction effect

[1] We have examined, using the finite difference time domain (FDTD) method for solving discretized Maxwell’s equations, the effect of upward extending wire, used for artificial lightning initiation from natural thunderclouds, and corona space charge emanated from this wire on the close ground‐level electric field (prior to lightning initiation). The wire current and charge transfer are also estimated. The lightning‐triggering wire is assumed to be perfectly conducting and extending vertically upward with a constant speed of v = 150 m/s. Owing to the limitations of the FDTD method, the wire radius is set to r = 0.27 m, larger than the actual radius (0.1 mm), but the results are not expected to be much influenced by this assumption. The corona space charge that emanated from the wire surface is represented by a conducting cylindrical sheath of outer radius r = 2, 4, 8, and 16 m, coaxial with the wire (the dynamics of corona discharge are not considered here). Other geometries of the corona space charge sheath are considered as well. It has been found that the results presented here are insensitive to the value of corona sheath conductivity ranging from 10−8 S/m to infinity. The corona space charge layer at the ground is simulated by perfectly conducting cylindrical tubes placed on the ground surface