A New Approximate Method for Lightning-Radiated ELF/VLF Ground Wave Propagation over Intermediate Ranges

Figure 7

The lightning-radiated vertical electric field peak value as a function of propagation distance for (a) the planar earth and (b) the spherical earth. The lightning current source shown in Figure 2 is adopted. The solid curves are the fitted results of average field peak value for earth conductivity ranges from 0.001 S/m to 4 S/m.

(a)

(b)