Results 271 to 280 of about 11,557,211 (324)

Geomorphology of spread F and characteristics of equatorial spread F

Journal of Geophysical Research, 1959
Between 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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Equatorial spread-F at Ibadan, Nigeria

Journal of Atmospheric and Terrestrial Physics, 1961
Abstract The characteristics of equatorial spread-F at Ibadan (magnetic latitude 3°S) are investigated including nocturnal, seasonal, solar-cycle and magnetic disturbance variations; and all of these are found to show marked correlations with corresponding changes in the height of the layer. For example spreading begins shortly after the evening rise
Lyon, AJ, Skinner, NJ, Wright, RW
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Role of equatorial ionization anomaly in the initiation of equatorial spread F

Journal of Geophysical Research: Space Physics, 1988
A comparative study is made of the changes in the latitudinal structure of the F region electron density at fixed altitudes in the Indian equatorial region on days with and without postsunset onset of equatorial spread F, using (N‐h) profile data of Ahmedabad (dip latitude 18.6°N), Waltair (dip latitude 10.6°N), and Kodaikanal (dip latitude 1.5°N).
R. Raghavarao, M. Nageswararao, J. Hanumath Sastri, G. D. Vyas, M. Sriramarao   +4 more
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Equatorial spread-F (ESF) and vertical winds

Journal of Atmospheric and Solar-Terrestrial Physics, 1999
Abstract The Equatorial Spread-F (ESF) phenomenon is recorded in ionograms as a hierarchy of plasma instabilities in the F-layer of the equatorial ionosphere. The ESF is characterized by irregularities in the plasma (electron and ion) density and electric field distributions perpendicular to the Earth’s magnetic field.
R. Raghavarao, R. Suhasini, H.G. Mayr, W.R. Hoegy, L.E. Wharton   +4 more
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Equatorial spread-F campaign over SHAR

Journal of Atmospheric and Solar-Terrestrial Physics, 1997
Abstract A RH-560 rocket instrumented with a Langmuir Probe and two pairs of double probes was launched from SHAR (dip 14 ° N) at 2130 hr LT (1ST) on 4 October 1988 during spread-F conditions. As a part of this campaign VHF scintillations at 136.1 MHz were also recorded, using the beacon onboard the geostationary satellite ETS-II (130 ° E).
H. Chandra, G.D. Vyas, H.S.S. Sinha, S. Prakash, R.N. Misra   +4 more
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Radio wave heating and equatorial spread-F

Journal of Atmospheric and Terrestrial Physics, 1987
Abstract High frequency radio waves passing through the F -region of the ionosphere can modify the spectrum of spread- F irregularities via a four wave parametric interaction. Non-linear coupling arises through the thermal gradient force. The growth rate is a sensitive function of the angle θ between the wave vectors of the incident wave and the ...
V.N. Laxmi, V.K. Tripathi
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Equatorial Spread-F and Tropospheric Tropical Disturbances

Journal of the Atmospheric Sciences, 1966
Equatorial spread-F and tropical disturbances, supplying data on typhoon, geomagnetic activity and atmospheric pressure ...
Kaichi Maeda, Victor L. Badillo
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On the occurrence of equatorial spread-F in the evening hours

Journal of Atmospheric and Terrestrial Physics, 1986
By comparing electron drift velocities at Jicamarca with corresponding ionograms and VHF radio scintillation records at Huancayo it has been shown that the day-to-day variability in the occurrence of equatorial spread-F irregularities in the post-sunset period depends critically on the time of reversal of the Sq electric field.
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Stochastic field theory for the ionospheric fluctuations in Equatorial Spread F

Chaos, Solitons & Fractals, 2019
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Materassi, Massimo
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Automatically identification of Equatorial Spread-F occurrence on ionograms

Journal of Atmospheric and Solar-Terrestrial Physics, 2015
Abstract F-region large-scale irregularities, also called plasma bubbles, are one of the most interesting equatorial ionospheric phenomena. These irregularities are generated in the equatorial region and afterwards extend to lower latitudes. They are one of the important topics of investigation in equatorial ionosphere electrodynamics and, therefore,
Valdir Gil Pillat, Paulo Roberto Fagundes, Lamartine Nogueira Frutuoso Guimarães   +2 more
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