Physical representations of the geomagnetic field

Abstract

The familiar Gaussian analysis of the geomagnetic field by the method of spherical harmonics clearly indicates that the predominant portion of the so‐called permanent magnetism of the Earth is due to internal causes. One of the striking results of this analysis is the dominance of the harmonics of the first degree. These first‐degree harmonics may be physically represented by a dipole at the center of the Earth with its south‐seeking end directed toward a point in latitude 78°5 north, longitude 291°2 east. An improved representation of the field which partially takes into account harmonics above the first degree is furnished by shifting this dipole 342 km toward a point in latitude 6°5 north, longitude 161°8 east [see 1 under “References” at end of paper].