Geophysical Journal | 2005 volume 27 5

Bimodal structure of response functions in weakly conducting atmosphere and generalized model of global electromagnetic sounding of the Earth

© Shuman V.N.

The problem of generating poloidal and toroidal fields are considered in the paper taking into account specified formulation of the Maxwell system equations. The structure of electromagnetic response on the Earth's surface produced by ionospheric-magnetospheric current systems is analyzed. It is noted that correct temporal and spatial analysis of long-period variations of the Earth's magnetic field, registered on the global net of geomagnetic observatories aimed at obtaining information on geoelectric properties of deep-seated structures must be realized within the limits of both three dimensional spherical models of the Earth and bimodal response structure within weakly conducting atmosphere. It is essential that the proposed approach foresees presentation of magnetic field in the form of summarizing classical Gaussian presentation. As a result prerequisites and possibilities appear to specify the classical scheme of deep electromagnetic sounding, which allow, according to the author's opinion, not only to preserve the most valuable classical achievements of the theory but also to trace some possible directions of further development of the method.

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