A survey of ionospheric cross-modulation (wave interaction or Luxembourg effect)

Existing theoretical and experimental knowledge is surveyed. The pioneer theory of Bailey and Martyn is restated in a form which relates it more closely to standard ionosphere theory. The experimental results are summarized in a form which enables the magnitude of the cross-modulation effect to be deduced approximately for any pair of stations. The way in which observations of cross-modulation can be used in ionospheric research is outlined.