Convection and diffusion modes of induced earth current


  • D. M. Summers


The physical interpretation which Price [1950] attached to the solutions of the pre-Maxwell equations is examined and the validity of linear circuit analogies to the problem of geomagnetic induction is questioned. If induced earth currents are solely diffusive, then geomagnetic induction data should be explicable in terms of near-field scattering theory. However, if the earth's inductive response comprises also a convective current mode similar to a linear circuit, then a more general formulation of the induction problem would be required. It is shown that the internal night-time Sq field can be attributed more easily to transient induction effects than to the global linear circuits proposed by Ashour and Price [1965].