Scintillation of cassiopeia a from artificial ionospheric inhomogeneities at 25, 240, and 290 MHz

Belikovich, V. V.; Benediktov, E. A.; Berezin, Iu. V.; Dobrushskii, L. A.; Razin, V. A.; Teplykh, A. I.; Tolmacheva, A. V.; Tomchinskii, A. M.; Shavin, P. B.

doi:10.1007/bf01034899

Cited by 3 publications

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“…Immediately after highpower HF facilities became available at Platteville, Colorado •Utlaut, 1970] and at Arecibo, Puerto Rico [Gordon et al, 1971], not only were the temperature enhancements observed, as predicted by Farley, but a host of unexpected phenomena resulting from the nonlinear interaction of high-power radio waves with the ionospheric plasma were also detected [Carlson and Duncan, 1977;Guterich, 1978;Fejer, 1979, and references therein]. Among these varied phenomena, electron density variations at ionospheric heights were detected as manifested by artificial spread F on ionograms, radio star and satellite scintillations and enhanced incoherent scatter signals from the perturbed regions [Georges, 1970;Rufenach, 1973;Allen et al, 1974;Thorne and Perkins, 1974;Pope and Fritz, 1974;Getmantsev et al, 1976;Duncan and Behnke, 1978;Erukhimov et al, 1979;Belikovich et al, 1979;Basu et al, 1980Basu et al, , 1983Frey and Gordon, 1982;Livingston, 1983;Frey et al, 1984]. Later, density variations were measured directly by satellite in situ probes [Farley et al, 1983].…”

Section: Introductionmentioning

confidence: 99%

Daytime scintillations induced by high‐power HF waves at Tromsø, Norway

Basu¹,

Stubbe²,

Kopka³

et al. 1987

J. Geophys. Res.

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During March 1984 the high-power HF heating facility located at Ramfjordmoen (69.6øN, 19.2øE geographic) near Tromso, Norway, was used to modify the ionospheric F region in the daytime. The intensity and phase scintillations of 250-MHz transmissions from the quasi,stationary polar beacon satellite were measured when the ray path from the observing site to the satellite intercepted the modified ionospheric volume. Narrow band spectral enhancements corresponding to an irregularity scale length of 750 m were detected in the intensity spectra when the radiated HF power developed an estimated power density of about 0.3 mW/m 2 at the height of reflection. Spectral enhancements at larger scales were not detected in the phase spectra. From the growth and decay of the intensity spectral enhancements during the successive 10-min "on" and 10-min "off" periods of the heater the e-folding growth and decay times of • 750 m irregularities were estimated to be on the order of 30 s and 2 min, respectively. The threshold power densities required for the generation of the observed irregularity scale sizes were calculated from the self-focusing instability theory of Cragin et al. (1977) by the use of ionospheric background parameters measured by the EISCAT radar. The theoretical estimates were found to be within a factor of 2 of the HF power densities employed in the experiment. The presence of Fresnel oscillations in the intensity and phase spectra were attributed to a limited irregularity layer thickness less than 50 km. By using the formulations of the thin phase screen theory, it was found that the observed intensity scintillations at 250 MHz correspond to irregularity amplitudes (AN/N) of 3% with an outer scale of 1 km. 11,149 11,150 BASU ET AL.' SCINTILLATIONS INDUCED BY HF WAVES AT TROMSO 73 72 7O $9 G8

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Section: Introductionmentioning

confidence: 99%

Daytime scintillations induced by high‐power HF waves at Tromsø, Norway

Basu¹,

Stubbe²,

Kopka³

et al. 1987

J. Geophys. Res.

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Investigation by backscatter radar of artificial irregularities produced in ionospheric plasma heating experiments

Бахметьева

Bubukina

Ignat’ev

et al. 1997

Journal of Atmospheric and Solar-Terrestrial Physics

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Studies of the self‐focusing instability at Arecibo

Farley¹,

LaHoz²,

Fejer³

1983

J. Geophys. Res.

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Precisely simultaneous radar and satellite measurements at the altitude of reflection of a strong HF heating wave above the Arecibo Observatory were made on June 7, 1977. Parametric instabilities produce strong enhancements in the plasma line and ion line incoherent scatter radar echoes. These echoes also exhibit periodic deep fading that is attributed to a self‐focusing instability. This explanation was confirmed by the in situ observation of electron density fluctuations with peak‐to‐peak amplitudes reaching at least 3% and a spatial dependence that corresponded closely to the radar fading pattern, at least for irregularity wavelengths ranging from a few hundred meters to a few kilometers. The correspondence implies that the radar fading is associated with the convection of the density irregularities through the radar beam. The radar and satellite observations also provided values for the important parameters of the ambient ionosphere, making possible a quantitative comparison of the data with existing theories of the self‐focusing instability. In particular, the agreement with the theory of Cragin et al. (1977) is fairly good.

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Scintillation of cassiopeia a from artificial ionospheric inhomogeneities at 25, 240, and 290 MHz

Cited by 3 publications

References 1 publication

Daytime scintillations induced by high‐power HF waves at Tromsø, Norway

Daytime scintillations induced by high‐power HF waves at Tromsø, Norway

Investigation by backscatter radar of artificial irregularities produced in ionospheric plasma heating experiments

Studies of the self‐focusing instability at Arecibo

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