Some Notes on the Interpretation of Rapid Fluctuations in Earth-Currents Observed in High Latitudes

Abstract

This paper shows that a periodically varying infinite linear current, or a periodically varying turbulent circular current of small radius (here approximated by a magnetic dipole with a changing dipole moment), in the ionosphere, which will give rise to magnetic variations of observed order of magnitude, is adequate for producing voltage differences in the ground of order 0 .1 to 1 volt per kilometer that are frequently observed in high latitudes during disturbed periods. It appears difficult to interpret the earth-current record in terms of its primary origin, unless the distribution of the perturbing magnetic field and that of electric conductivity of the earth are both adequately known. However, the earth-current record is a good indicator of the upper atmospheric disturbance in the polar regions.