Influence of finite ground conductivity on the fields of a vertical traveling wave of current

Following Wait (1998), we deal mainly with the radiation fields of a vertically directed and attenuated line current (lightning) above a plane Earth. In the present case, the conductivity and permittivity of the ground modify the radiation pattern in the air compared with the usually assumed case of infinite conductivity. The effect is quite striking at low elevation angles where the radiation pattern now has a null for grazing angles.