Doppler frequency variations in the field-aligned scattering of VHF waves by artificial irregularities of the ionosphere

Коровин, А. В.; Nasyrov, A. M.; Proskurin, E. V.; Yagnov, N. N.

doi:10.1007/bf01034779

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…Early measurements of AFAI's having short spatial scales (1-10 m) across geomagnetic field lines were made at Platteville, Colorado, in the early 1970's (e.g., Radio Science, volume 9, number 11, and Minkoff and Kreppel [1976]). This work was followed by several Russian investigations [e.g., Belenov et al, 1977;Korovin et al, 1982]. More recently, radar observations of AFAI's have been made using the auxiliary HF facility located near Arecibo Observatory in Puerto Rico [Coster et al, 1985].…”

Section: Introductionmentioning

confidence: 99%

Observations of E region irregularities generated at auroral latitudes by a high‐power radio wave

et al. 1985

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In September 1983 a series of ionospheric modification experiments was performed in Scandinavia using the high‐frequency (HF) heating facility located near Tromsø, Norway. The experiments were designed to study the production of geomagnetic field‐aligned irregularities in the auroral E region by a powerful HF radio wave. In this initial report, observations of 3.2‐m irregularities made with a mobile 46.9‐MHz field radar are presented. When ionospheric conditions are correct, irregularities having peak cross sections of about 104 m² are excited in the E region over Tromsø. The present results are consistent with theoretical studies which indicate that it is easier to generate short‐scale field‐aligned irregularities at locations where the geomagnetic dip angle is large. When the HF‐induced radar echo at 46.9 MHz is strong, the e‐folding growth times of the echo power are typically between 50 and 150 ms. However, when the E region echo over Tromsø is weak, the growth period can range from seconds to tens of seconds. The irregularities generated by the HF wave often exhibit dynamic structure both in time and in space. In general, the observations provide experimental support for instability theories that employ interactions near the upper hybrid resonance to drive the artificial irregularities. The results also indicate that naturally occurring irregularities may at times play a key role in the excitation of HF‐induced irregularities in the auroral E region. Additional processes are probably required to explain the slower irregularity growth rates often observed when radar echoes are relatively weak and occasionally observed even for relatively strong signals.

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Section: Introductionmentioning

confidence: 99%

Observations of E region irregularities generated at auroral latitudes by a high‐power radio wave

et al. 1985

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“…These experiments were followed by a number of Russian investigations (e.g. Belenov et al, 1977;Korovin et al, 1982). More recently, Hedberg et al (1983Hedberg et al ( , 1986 and Hanuise et al (1986) have detected HF backscatter from arti®cial FAI in the auroral F-region, produced by the EISCAT high power facility at Tromsù, Norway (Rietveld et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Spatial observations by the CUTLASS coherent scatter radar of ionospheric modification by high power radio waves

et al. 1997

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Abstract. Results are presented from an experimental campaign in April 1996, in which the new CUTLASS (Co-operative UK twin-located Auroral Sounding System) coherent scatter radar was employed to observe arti®cial ®eld aligned irregularities (FAI) generated by the EISCAT (European Incoherent SCATter) heating facility at Tromsù, Norway. The distribution of backscatter intensity from within the heated region has been investigated both in azimuth and range with the Finland component of CUTLASS, and the ®rst observations of arti®cial irregularities by the Iceland radar are also presented. The heated region has been measured to extend over a horizontal distance of 170 AE 50 km, which by comparison with a model of the heater beam pattern corresponds to a threshold electric ®eld for FAI of between 0.1 and 0X01 V/m. Di erences between ®eld-aligned and vertical propagation heating are also presented.

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Modern problems of ionospheric modification

Gurevich¹

1999

Radiophys Quantum Electron

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Doppler frequency variations in the field-aligned scattering of VHF waves by artificial irregularities of the ionosphere

Cited by 7 publications

References 4 publications

Observations of E region irregularities generated at auroral latitudes by a high‐power radio wave

Observations of E region irregularities generated at auroral latitudes by a high‐power radio wave

Spatial observations by the CUTLASS coherent scatter radar of ionospheric modification by high power radio waves

Modern problems of ionospheric modification

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