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Unresolved spread-f as a result of pulse spreading
Journal of Atmospheric and Terrestrial Physics, 1977Abstract The shape of pulses returned to an ionosonde after reflection from an electron density profile containing irregularities which cause the composite profile to be non-monotonic have been calculated. The effect of the ionosonde receiver on these returned pulse shapes has been simulated by band-pass filtering the received frequency spectrum and ...
I Robinson, P.L Dyson
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Geomorphology of spread F and characteristics of equatorial spread F
Journal of Geophysical Research, 1959Between magnetic latitudes 20°N and 20°S there is a well defined region where spread F is a normal occurrence on magnetically quiet days. Equatorial spread F is a night-time phenomenon that begins between 1900 and 2200 by a characteristic doubling of the layer and an increase in virtual height, indicating a vertical velocity.
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The belt of equatorial spread-F
Journal of Atmospheric and Terrestrial Physics, 1960Abstract The morphology of the belt of equatorial spread-F at sunspot maximum is investigated, using I.G.Y. data, for magnetically quiet and magnetically disturbed conditions respectively. The belt is found to extend from about 30°S to 30°N in magnetic latitude and to have a region of very high incidence, exceeding 90 per cent for the early part of ...
Lyon, AJ, Skinner, NJ, Wright, RWH
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Journal of Atmospheric and Terrestrial Physics, 1970
Abstract Spread- F echoes are not due to partial reflection from small irregularities. Rather they are due to total reflection from large tilted surfaces of ionization. The geometry of these surfaces is examined using ionograms and airglow observations, together with Australian experiments reported in the literature.
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Abstract Spread- F echoes are not due to partial reflection from small irregularities. Rather they are due to total reflection from large tilted surfaces of ionization. The geometry of these surfaces is examined using ionograms and airglow observations, together with Australian experiments reported in the literature.
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Duration of equatorial spread F
Nature, 1975IT is well established1–3 that the spread-F phenomenon, which is observed as diffuse echoes on the ionograms is a common feature during night time between the dip latitudes 20°N and 20°S. Based on the study of ionograms and published monthly f0F2 bulletins, morphological features of spread F have been reported for several equatorial stations1,4–10 ...
V. V. SOMAYAJULU +2 more
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A study of equatorial spread-F
Journal of Atmospheric and Terrestrial Physics, 1963Data from seven stations ranging in magnetic dip from 0° to 44°N have been analysed to study night time and seasonal variations of spread-F through nearly half a solar cycle. It is observed that the inhibition of spread-F due to geomagnetic activity is maximum in the equinoxes.
S. Rangaswamy, K.B. Kapasi
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AIP Conference Proceedings, 1992
Because of its complex nature, the knowledge of spread F is not commensurate with the long period of its study. Rockets, satellites and radar systems have greatley advanced observational information on spread F. We have outlined some of these observations and presented information on certain morphology and characteristics of both the equatorial and ...
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Because of its complex nature, the knowledge of spread F is not commensurate with the long period of its study. Rockets, satellites and radar systems have greatley advanced observational information on spread F. We have outlined some of these observations and presented information on certain morphology and characteristics of both the equatorial and ...
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Journal of Atmospheric and Terrestrial Physics, 1981
Our understanding of equatorial spread-F (ESF) phenomena has progressed significantly in the past several years. ESF phenomena involves ionospheric irregularities spanning some 5–6 orders of magnitude in scale size. The largest scale sizes, on the order of many kilometers, are thought to be caused by a plasma fluid type Rayleigh-Taylor instability ...
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Our understanding of equatorial spread-F (ESF) phenomena has progressed significantly in the past several years. ESF phenomena involves ionospheric irregularities spanning some 5–6 orders of magnitude in scale size. The largest scale sizes, on the order of many kilometers, are thought to be caused by a plasma fluid type Rayleigh-Taylor instability ...
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On a model of artificial F-spread in the ionosphere
Radiophysics and Quantum Electronics, 1996The results of a complex experiment on the synchronous observation of geostationary-satellite signals and of reflected HF signals of the vertical-sounding station in the course of ionosphere modification by powerful short waves are analyzed using the method of refractive scattering of radio waves.
V. A. Alimov, A. V. Rakhlin
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Classification of spread-F ionograms
Journal of Atmospheric and Terrestrial Physics, 1962Abstract Scaling of original ionograms obtained in the polar regions has lead to a classification scheme for spread-F ionograms. Defined are three types of frequency spreading (spreadish-F, furcated-F and spurred-F) and one type of range spreading. Each type is subdivided into species.
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