Review of Radio-Frequency, Non-linear Effects on the Ionosphere

Abstract

Radio waves have inadvertently modified the Earth's ionosphere since the Luxembourg observations of Tellegen in 1933 and perhaps since Marconi in 1901. The history of this ionosphere modification by radio waves beginning with Marconi, touching on the Luxembourg effect, its explanations and its early use to deduce the properties of the lower ionosphere in the 1930s have been outlined. The measurements became more sophisticated in the 1950s leading to the Ginzburg and Gurevich proposal in 1960 for high powered, high frequency modification experiments in the upper ionosphere. Beginning in 1970 major radio facilities were available to induce changes in the ionospheric plasma accompanied by an array of diagnostics for observing the effects. A summary of these effects up to 1986, where the natural plasma of the ionosphere is treated as a laboratory to study the physics of the medium, is presented. The work summarized was done in the USSR, the USA and Western Europe. The experimental and theoretical contributions provide a rich store of information on plasma physics. It is suggested that there is a special opportunity for east-west cooperation and collaboration.