Small-scale spatial fluctuations of a v.l.f. wave field in the ionosphere in the zone close to the transmitter

The FR-1 satellite experiment, the characteristics of which have been described in a previous paper by Storey, has provided information on the penetration of upgoing v.l.f. waves in the ionosphere. The experiment involves a transmitter located at Sainte-Assise (France), radiating 20 kW on 16.8 kHz, and a receiver aboard the satellite at 750 km altitude. An account of the first results concerning the mean level, and also the large and small-scale spatial fluctuations of the v.l.f. field, has been published already by the author. In this letter we analyse more carefully the problem of the spatial fluctuations of the v.l.f. field on the small scale (less than 100 km).