Results 261 to 270 of about 87,973 (293)

Three-Dimensional Modeling of Equatorial Spread F

2011
The Naval Research Laboratory (NRL) has recently developed a three-dimensional code to study equatorial spread F (ESF). The code is based on the comprehensive NRL 3D ionosphere model SAMI3 and includes a potential equation to self-consistently solve for the electric field.
J.D. Huba, G. Joyce, J. Krall
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Onset conditions for equatorial spread F

Journal of Geophysical Research: Space Physics, 1992
The problem of day‐to‐day variability in the occurrence of equatorial spread F (ESF) is addressed using multidiagnostic observations and semiempirical modeling. The observational results are derived from a two‐night case study of ESF onset conditions observed at Kwajalein Atoll (Marshall Islands) using the ALTAIR incoherent scatter radar and all‐sky ...
Michael Mendillo, Jeffrey Baumgardner, Xiaoqing Pi, Peter J. Sultan, Roland Tsunoda   +4 more
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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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Hindcasting of Equatorial Spread F Using Seasonal Empirical Models

Journal of Geophysical Research: Space Physics, 2018
AbstractThe role of gravity waves in modulating equatorial spread F (ESF) day‐to‐day variability is investigated using ionosonde data at Trivandrum (geographic coordinates, 8.5°N, 77°E; mean geomagnetic latitude −0.3°N) a magnetic equatorial location. A novel empirical model that incorporates the combined effects of electrodynamics and gravity waves in
R. P. Aswathy, G. Manju
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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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JULIA radar studies of equatorial spread F

Journal of Geophysical Research: Space Physics, 1998
This paper presents coherent scatter radar observations of plasma irregularities in the equatorial F region ionosphere made with the JULIA (Jicamarca unattended long‐term studies of the ionosphere and atmosphere) radar and discusses model equations and simulations pertinent to their interpretation.
D. L. Hysell, J. D. Burcham
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Control of equatorial spread-F by the F-layer height

Journal of Atmospheric and Terrestrial Physics, 1966
Abstract The dependence of equatorial spread-F occurrence on the height of the layer is examined in detail in the case of two equatorial stations viz. Kodaikanal and Huancayo, lying close to the magnetic equator. The percentage of occurrence associated with different heights is found to vary with time, season and longitude.
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Equatorial spread-F: recent results and outstanding problems

Journal of Atmospheric and Terrestrial Physics, 1985
Abstract Recent results and outstanding problems in the field of equatorial spread-F are reviewed. The discussion is organized about four distinct wavelength regimes: long (≳ 20 km). intermediate (20 km–100 m). transitional (100 m–10 m) and short (≲ 10 m).
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ALTAIR Radar Study of Equatorial Spread F.

1981
Abstract : The results of research on equatorial spread-F (ESF) phenomena obtained by using two backscatter radars, ALTAIR and TRADEX, are summarized. The radar measurements were made in support of three rocket campaigns conducted from the Kwajalein Atoll during the summers of 1977 through 1979.
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Imaging coherent backscatter radar studies of equatorial spread F

Journal of Atmospheric and Solar-Terrestrial Physics, 1999
Abstract A new interferometric imaging technique has been used at Jicamarca to study the morphology and dynamics of plasma irregularities occurring during spread F conditions. The technique produces two-dimensional, in-beam images of the coherent scatter from these irregularities, instantaneously mapping the structure of the underlying plasma ...
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