Radiation from a current filament above a homogeneous Earth, with application to micropulsations

Abstract

If electromagnetic radiations from ionospheric current systems are considered sources of micropulsations, it becomes instructive to examine the following model problem: What are the electric and magnetic fields in the vicinity of a plane, homogeneous earth due to a line current source above this model earth? As the micropulsation frequencies are quite low (order of 1 cps), the nearfield considerations become significant. The solution for this near field problem is presented and the fields at the earth's surface are evaluated for a set of parameter values chosen to approximate an ionospheric source at a typical micropulsation frequency.

The Electric and Magnetic Fields in a Stratified Flat Conductor for Incident Plane Waves

“…This is to be expected since the plane-wave model assumes a very distant uniforill current sheet of infinite extent and a horizontally layered conducting halfspace, whereas the magnitude and distribution of the observed vertical component are associated with the linear dimensions of the source and conductor. Other n~odels, such as a plane conducting homogeneous earth in the near field of a line source studied by Law and Fannin (1961) and a cylindrical homogeneous earth in the near field of a line current studied by Weaver (1961), yield ratios nearer the observed values. However, mathenlatically the planewave inodel lends itself more readily to studying the effect of inhomogeneities in the conducting substratum.…”

Mining Geophysics, Volume II, Theory

“…If we now assume that Ao~0, which is of course the quasi-static approximation, we can write the electric field as AI L* + t(h -z) J The above development follows that of Law and Fannin (,1961) in a general way. This problem was solved in an approximate manner as early as 1926 by Carson (1926).…”

Magnetic field at the Earth's surface produced by a horizontal line current

“…The b'asic equations have been given by Price [1950] and in equivalent forms by Law and Fannin [1961], Park [1973], and many other authors. We shall use the formulas of Park [1973], which are closely analogous to those of Law and Fannin, and the notation of…”