History of Modification of the Ionosphere by Radio Waves

The Luxembourg effect

In the early 1930s a high power radio broadcasting station was built in Luxembourg. Tellegen (1933) reported that the modulation of the Luxembourg station could be heard in the background of a programme transmitted from Beromunster and received at Eindhoven. Soon after, Bailey and Martyn (1934) suggested that the effect was caused by the powerful Luxembourg transmitter modifying the radio propagation characteristics of the ionosphere. When the Beromunster signal passed through this region its propagation was affected by the modified ionospheric conditions, and in this way amplitude modulation from the Luxembourg signal was transferred to the Beromunster signal.

The ionosphere as a plasma laboratory

The Luxembourg effect became known as cross-modulation, and scientists began to explore the possibilities of utilising high power radio waves in controlled ionospheric experiments. This was the beginning of employing modification of the ionosphere to complement plasma experiments in the laboratory. Bailey and Goldstein were among the first to suggest this, when in 1958 they suggested the use of radio waves near the electron gyrofrequency to control electron temperatures. Many other experiments were suggested, for example, Ginzburg and Gurevich (1960) suggested modification of the F-region ionosphere.

Ionospheric heating

The early modification experiments were concerned with using high power radio waves to produce small changes in ionospheric properties, such as collision rates, and then investigating how this affected the propagation of low power diagnostic waves. From these experiments developed ionospheric heating, where the high power radio wave was employed to produce large scale electron temperature enhancements. Showen (1972) found enhanced electron temperatures in measurements taken from the Arecibo incoherent scatter radar, when utilising a high power 40 MHz wave to modify the ionosphere. Experiments like this demonstrated that ionospheric modification was possible and paved the way for modification facilities such as those at Arecibo in Puerto Rico, Tromso in Norway, and Fairbanks in Alaska.


Bailey, V.A. and L. Goldstein, Control of the ionosphere by means of radio waves, J. Atmos. Terr. Phys., 12, 216, 1938

Bailey, V.A. and D.F. Martyn, Influence of electric waves in the ionosphere, Phil. Mag., 23, 369, 1934

Ginzburg, V.L. and A.V. Gurevich, Nonlinear phenomena in a plasma located in an alternating electromagnetic field, Usp. Fiz. Nauk. (USSR), 201, 70; Sov. Phys. Ups. (English translation), 3, 115 and 175, 1960

Showen, R.L., Artificial Heating of the Lower Ionosphere, J. Geophys.Res., 77,1923-1933, 1972

Tellegen, B.D.H., Interaction between radio waves?, Nature, 131, 840,1933