Fine structure of the ionospheric region E

Equatorial spread F.

“…Figure 22 shows this feature for the observed slant trace in figure 20. The linearity of slant -sporadic -E traces has been noticed previously by Agy (private communication to Smith and Knecht, 1957) and by Whale (1951 Another technique revealing F-layer motions is that of following large-scale ionospheric distortions as they occur at spaced ionosondes.…”

“…Renau ( 1959a, 1959b, i960) has considered a number of spreadmodels. Among these are sharp ledges of ionization similar to those proposed by Whale (1951) ; (b) propagation is confined to the vertical eastwest plane through the equatorial ionosonde; (c) only the ordinary ray of magnetoionic propagation theory is considered; Condition (e) implies that an echo may be obtained over any ray path, or combination of ray paths, connecting the ionosonde and the assumed scattering center.…”

“…The effect is strong enough to suggest the prediction of spread F from the state of magnetic activity ( Wright , 1959) • Spread F and radio-star scintillation have been correlated in terms of monthly and annual means ( Dagg ,195Tb), their diurnal variation (Ryle and Hewish, 1950;Koster and Wright , i960), and individual events (Briggs, 1958j Brenan , i960;Wild and Roberts, 1956;Wright , Koster , and Skinner , 1956). The correlation is clearly positive for both equatorial and high-latitude stations.…”

A review of some recent work on mid-latitude spread-F occurrence as detected by ionosondes.

“…Various methods of detection have been used, but most of the investigations have involved rocket flights (see e.g., WHALE, 1951;ELLYETT and WATTS, 1959;BEDINGER et al,1968). Further, experimental evidence of small-scale stratifications was found recently in two middle-atmosphere regions.…”

Theory of overhead nonblanketing sporadicE

“…Introduction. Whale [1951] presented a theory of sporadic E based on the hypothesis that the height dependence of electron density in the E region consists of outward-thrusting 'ledges' in a parabolic E layer. This theory predicts results in agreement with the main features of the observational data.…”