Simulating the earth's induction effects on substorm data recorded at midlatitude stations  The threedimensional problem
Abstract
A problem in modeling external current systems from groundbased magnetic observations is the evaluation of the earth's induction effects. Though it is difficult to represent accurately the effects of induced currents flowing inside the earth, they can be approximated when global rather than local electrical properties of the earth are concerned. For this purpose, two general classes of earth models can be used: models which reduce the earth to a superconductor (either at the surface or at some depth); and the models in which the earth is represented by a body of finite conductivity (either uniform or layered). These two earth models are tested with respect to substorm modeling from midlatitude data (i.e., when neither the curvature of the earth nor the threedimensional nature of the substorm current system can be neglected). The conclusions are almost identical to those obtained previously with high latitude data. Thus, for most problems of substorm modeling from groundbased magnetic observations, it is sufficient to treat the earth as a superconductor.
 Publication:

Journal of Geomagnetism and Geoelectricity
 Pub Date:
 1977
 DOI:
 10.5636/jgg.29.81
 Bibcode:
 1977JGG....29...81M
 Keywords:

 Atmospheric Electricity;
 Data Recording;
 Geomagnetism;
 Magnetic Induction;
 Magnetic Storms;
 Midlatitude Atmosphere;
 Dynamo Theory;
 Earth Core;
 Earth Crust;
 Earth Surface;
 Electric Current;
 Magnetic Signatures;
 Mathematical Models;
 Superconductors;
 Geophysics