Inductive coupling between idealized conductors and its significance for the geomagnetic coast effect

Abstract

A problem of current interest is the inductive coupling between an ocean, a solid earth conductor and a conductosphere. The anomaly of this configuration is modelled by (i) the inductive response of a two-dimensional system consisting of two thin half sheets and an underlying thin whole sheet or (ii) the superposition of the responses of two related systems, each consisiting of only one of the two half sheets and the whole sheet. The conductivity of these conducting planes is assumed to be perfect, and rigorous solutions for the erived by conformal mapping. induced magnetic fields are a comparison between the anomalies (i) and (ii) permits us to ascertain the degree of inductive coupling between the idealized conductors. This establishes a reference for estimating the inductive coupling between more realistic conductors and may therefore assist in the interpretation of complicated magnetic variation anomalies in coastal regions. Our substitute configurations can also be used directly for the rapid modelling of the inductive response of the earth in the vicinity of coastlines. This is demonstrated by analyzing some field data from the recent literature.