Reflection and transmission of radio waves at a continuously stratified plasma with arbitrary magnetic induction

Abstract

A flexible theoretical model plas ma which can be deformed to fi t most mea s ured elect ron-ion-altitude profiles i. 3 e mployed t ogether wi th a va ila ble geophysical dat a on t he ionosphere to evahlate reflections and trans missions durin g quiescen t and disturbed propagation conditions. The refl ect ions and t ra ns mi ssions in t he ionospher e are determin ed rigorously with t he aid of th e classica l mag neto-ionic t heory. The complex indexes of r efr ac tion of t he medium are dedu ced, and a coupling in t he plas ma betwee n ordinar y a nd extraordinary, upgoing a nd down going mode of propagation is investigat ed. Th e corres ponding refl ection a nd t ransmi ssio n coeffici en ts are then ca lculated, a nd cer tain phenomena which can be exp ected as a r es ult o f the action of a solar di sturbance on t he r eflection process are predicted. Th e di sturbance of solar origin, investigated as a n application of developed t echniques, influences the refl ected and trans mitted LF wa ves in th e lower ionosph ere in a complicat ed manner. Howe ver, the high ab orption phenom ena exhibited by high fr equ encies do not see m t o exist for t he plas ma profiles investigated with the classical magneto-ionic theory. Th e electron-collision frequ e nci es of the classical magnetic-ionic theory ar e modifi ed to introduce a collis ion fr equ ency proportional to the electron energy, and the changes necessary in th e formulfttion of the classical theory as a r es ult of such a consid eration arc presented.

Propagation in nonuniform waveguides with impedance walls

“…We will restrict ourselves to the case of a flat earth and a sharply bowlded homogeneous ionosphere. While this model is rather rough by today's standards [Johler, 1962 ;Johler and Harper, 1962], it serves well the purpose of this initial study on this method of attack.…”

Propagation of electromagnetic waves through a continuously varying stratified anisotropic medium

“…The equations are first developed for an arbitrary number of homogeneous layers, a problem considered by Johler and Harper [1962]. A different system of representation is used in th is study, allowin g the number of layers to be increased by multiplying together more and more matrices of constant (4 X 4) size rather than by increasing the size of a single matrix.…”

“…The earth's magn etic field is included since it is expected to allow propagation through the ionosphere (whistler mod es) at some fr equencies and angles of incidence. It is assumed to have constant strength but to be at an arbitrary angle to the plane of stratification.The equations are first developed for an arbitrary number of homogeneous layers, a problem considered by Johler and Harper [1962]. A different system of representation is used in th is study, allowin g the number of layers to be increased by multiplying together more and more matrices of constant (4 X 4) size rather than by increasing the size of a single matrix.…”

The Development of Loran-C navigation and timing

“…It may be noted that the distances from Johannesburg to all three of the East Coast transmitters are nearly the same, but only the southernmost transmitter could be received. The influence of the earth's magnetic field on the ionosphere (Johler and Harper, 1962) very probably accounts for the observations, but uncertainties about the electron density make it difficult to draw positive conclusions.…”

“…It has also been observed that the higher order hops are subject to large amplitude variations, but the amplitude variations of any one hop seem to be independent of, or at least, show no obvious correlation with the amplitude variations of the other hops. Doherty (1962) proposed, andHarper (1962) have shown, theoretically, that a sparsely ionized region below the D layer could produce considerable attenuation without appreciable phase shift. If it is assumed that such a sparsely ionized region is timevariable, such a mechanism could explain both the day and night amplitude variations that are not accompanied by phase shifts.…”