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10 1
Satellite horizontal
10 0
10 21
HF
Rottger
10 22
Rocket vertical (4)
10 23
10 24
10 25
10 26
10 27
10 28
10 29
10 210
10 211
10 212
10 213
10 22
10 21
10 0
10 1
10 2
10 3
10 4
Wavenumber (km 21 )
Figure 4.5b Composite spectrum of horizontal and vertical plasma density fluctua-
tions. The rocket data are from the second Kwajalein campaign (1990) and the satel-
lite data are from AE-E. The HF data were deduced from data similar to Fig. 4.12.
The vertical lines correspond to the wave number that scatters the Jicamarca and Altair
radar signals. [After Kelley and Hysell (1991). Reproduced with permission of Pergamon
Press.]
Forward scatter, or “scintillation,” measurements have provided information
on structure in the intermediate wavelength range (100-1000m), since, at the
radio frequencies typically used for these experiments, the scale of the irregular-
ities that do the scattering is in that range (Basu et al., 1978). In the example
shown in Fig. 4.6, the VHF scintillation intensity (lower trace) continues for
a considerable time after the most intense 3m backscatter ends. This shows
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