Scattering of radio waves by periodic artificial ionospheric irregularities

Belikovich, V. V.; Benediktov, E. A.; Itkina, M. A.; Mityakov, N. A.; Terina, G. I.; Tolmacheva, A. V.; Shavin, B. P.

doi:10.1007/bf01037724

Cited by 21 publications

(26 citation statements)

References 3 publications

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“…This may be indicative of the formation of irregularities in the F region and so this technique could prove to be of value when combined with other measurements of the heated region. When Fejer et al (1984) performed a similar experiment at Arecibo, they found that the ratio of the scattered API power to specularly reflected power ''was about 10\, considerably higher than the value of about 2.5;10\ mentioned by Belikovich et al (1977)''. In our data the reflected wave was saturated most of the time, so it is difficult to compare with the scattered signal.…”

Section: F-region Echoesmentioning

confidence: 88%

“…By measuring the period of API oscillation, the ion-acoustic frequency, and hence the electron and ion temperatures, could be estimated (Belikovich et al, 1977). Fejer et al (1984) measured F-region API at the low-latitude Arecibo heating facility, and found the ratio of scattered to reflected power to be 10\, or about 40 dB greater than that measured by Belikovich et al (1977), concluding that anomalous absorption must have been present in the Russian experiments.…”

Section: Previous Workmentioning

confidence: 97%

“…The mechanism of formation of these F-region irregularities was in terms of the ponderomotive force as discussed in several papers (e.g. Belikovich et al, 1977Belikovich et al, , 1978aVarshavskii, 1978). Tolmacheva (1980) extended the theory to include the effect of the geomagnetic field.…”

Section: Previous Workmentioning

confidence: 99%

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Artificial periodic irregularities in the auroral ionosphere

Rietveld

Turunen²,

Matveinen³

et al. 1996

Ann. Geophys.

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Abstract. Artificial periodic irregularities (API) are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at midlatitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR) data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75-115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50-70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the data below 60 km but is larger above 60 km by a factor of up to 2 at 64 km. The comparisonsCorrespondence to: M. T. Rietveld with the model are considered to be a good basis for more refined comparisons.

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Section: F-region Echoesmentioning

confidence: 88%

Section: Previous Workmentioning

confidence: 97%

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Artificial periodic irregularities in the auroral ionosphere

Rietveld

Turunen²,

Matveinen³

et al. 1996

Ann. Geophys.

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“…Seliga 17 showed the feasibility of generating artificial periodic plasma irregularities during the reflection of strong radio waves from the F-region ionosphere. Belikovich et al 18 observed such a grating in the lower ionosphere using high-power ground-based transmitter. Subsequent experiments showed that APIs are formed in the field of a standing wave which results from interference between the incident and the reflected wave within a height interval from about 60 km up to the reflection point of the strong radio wave.…”

Section: Introductionmentioning

confidence: 97%

Grating formation by a high power radio wave in near-equator ionosphere

2011

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The formation of a volume grating in the near-equator regions of ionosphere due to a high power radio wave is investigated. The radio wave, launched from a ground based transmitter, forms a standing wave pattern below the critical layer, heating the electrons in a space periodic manner. The thermal conduction along the magnetic lines of force inhibits the rise in electron temperature, limiting the efficacy of heating to within a latitude of few degrees around the equator. The space periodic electron partial pressure leads to ambipolar diffusion creating a space periodic density ripple with wave vector along the vertical. Such a volume grating is effective to cause strong reflection of radio waves at a frequency one order of magnitude higher than the maximum plasma frequency in the ionosphere. Linearly mode converted plasma wave could scatter even higher frequency radio waves.

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“…One requirement in optimizing the ELFNLF generation efficiency is knowledge of the electron density profile in the modified region. The Artificial Periodic Irregularities (API) technique [3] has been successful in reconstntcting electron density profiles in the E-Region at Sura and Tromso [4], but has not yet been implemented at HAARP. Details and results of the HAARP experiment will be discussed.…”

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confidence: 99%

Orientation of Z-pinch instabilities from an intense aurora as recorded in antiquity: South America

Scott

Peratt

The 31st IEEE International Conference on Plasma Science, 2004. ICOPS 2004. IEEE Conference Record - Abstracts.

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In the first presentation' we reported an analysis of a GPS database of petroglyphs recorded in the westem US and British Columbia. These results indicated that a plasma flowing into the Earth's south magnetic pole produced an intense aurora seen worldwide. In this paper we report the findings of logged petroglyphs in Venezuela, Guyana, Surinam, French Guiana and northem Brazil as well as some preliminary results from 93 countries. With decreasing longitude towards the Greenwich Meridian, petroglyphs appear to take on an increasingly easterly orientation. This swing from south to east can be tracked through the eastem US and the Caribbean Islands to the petroglyph sites shown below (dots), between 0 and 8 degrees north and 51 to 62 degrees west?The spatial and temporal evolution of electrojet modulation, and the ELFNLF signal produced by ionospheric modification, is currently being studied in support of a planned experiment using the HAARP phased-array ionospheric heater [I]. Theory and simulation concentrated on the EMHD response of the maguetoplasma to an applied current pulse [2]. The collisionless case for zero-mass electrons is solved analytically. For finite electron mass, the response equations are solved by means of a numerical EMHD field solver. In the collisional case, a treatment using the Fokker-Planck equation, with the corresponding It6 stochastic differential equations, is planned. One requirement in optimizing the ELFNLF generation efficiency is knowledge of the electron density profile in the modified region. The Artificial Periodic Irregularities (API) technique [3] has been successful in reconstntcting electron density profiles in the E-Region at Sura and Tromso [4], but has not yet been implemented at HAARP. Details and results of the HAARP experiment will be discussed.

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Scattering of radio waves by periodic artificial ionospheric irregularities

Cited by 21 publications

References 3 publications

Artificial periodic irregularities in the auroral ionosphere

Artificial periodic irregularities in the auroral ionosphere

Grating formation by a high power radio wave in near-equator ionosphere

Orientation of Z-pinch instabilities from an intense aurora as recorded in antiquity: South America

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