Terrestrial extremely low frequency noise spectrum in the presence of exponential ionospheric conductivity profiles

Abstract

Calculations by Raemer of the terrestrial ELF noise spectrum which are based on a sharply bounded homogeneous ionosphere of frequency-dependent height and conductivity are extended to a nonhomogeneous ionosphere of exponential conductivity profile. The exponential ionosphere model provides slightly lower resonant frequencies and less damping of the resonant peaks than the sharply bounded ionosphere. The exponential model improves the agreement with noise spectrum measurements by Balser and Wagner.