Resonances of the Thin‐Shell Model of the Earth‐Ionosphere Cavity With a Dipolar Magnetic Field

A coupled multimode analysis technique is applied to a model of the earth-ionosphere cavity at ELF in which the ionosphere is replaced by a thin, anisotropic shell. The unique feature of the analy. sis is that it is capable of illustrating the effects of a dipolar form of geomagnetic field. Numerical values of the cavity resonant frequencies and quality factors for several values of electron density and collision frequency are presented for both a homogeneous and a dipolar magnetic field configuration. The main purpose of the paper is to demonstrate that a coupled multimode analysis is applicable to such nonsymmetrical configurations.