Propagation of ELF Pulses in the Earth‐Ionosphere Cavity and Application to ‘Slow Tail’ Atmospherics

Abstract

The propagation of ELF electromagnetic pulses in the earth‐ionosphere cavity is considered with special reference to ‘slow tail’ atmospherics. The problem is formulated in the frequency domain; inversion to the time domain is achieved by a numerical evaluation of the Fourier transform. The propagational model employed involves a spherical earth with a concentric, spherically stratified, inhomogeneous, isotropic ionosphere. The pulse source assumed represents the median return stroke of a lightning discharge. Both short‐range propagation and long‐range propagation are considered. Particular attention is paid to the nature of the electric‐ and magnetic‐field components of the pulse in the vicinity of the antipode of the source. Copyright 1970 by the American Geophysical Union.