Some Aspects of Diffraction Theory and their Application to the Ionosphere

Ratcliffe, J.A.

doi:10.1088/0034-4885/19/1/306

Cited by 479 publications

(163 citation statements)

References 39 publications

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“…This is most conveniently performed by means of a phase-sensitive interferometer with variable spacing between the aerials. Ratcliffe (1956) has demonstrated that the fringe visibility function V(,) is identical with PIW. Hence the spacing of the interferometer aerials for which the fringe visibility has been reduced to exp( -1) is a measure of ' I.…”

Section: (B) Angular Spectrum Of Scattered Radiationmentioning

confidence: 95%

“…The relationship of PfW and 1 F(S) 12 to the scale size of the electron irregularities in the diffracting region has been presented rather clearly by Ratcliffe (1956). If the irregularities possess a Gaussian autocorrelation function…”

Section: (B) Angular Spectrum Of Scattered Radiationmentioning

confidence: 98%

“…The scale length of the intensity fluctuations varies considerably, but with cp~ ~ 1 and equation (8) satisfied so that the observer is in the Fraunhofer region (9) (e) Effect of Spherical Wave Front Ratcliffe (1956) and Pisareva (1958) have discussed the case of an observer and point source distant Zl and Z2 respectively from the diffracting screen. They show that the actual distance should be replaced by an equivalent distance Z = Z l Z2!…”

Section: (D) Intensity Fluctuations Across the Ground Planementioning

confidence: 99%

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The Solar Wind and Jovian Decametric Radio Emission

Slee¹,

Higgins²

1968

Aust. J. Phys.

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Spaced-receiver observations of the 19·7 MHz radio emission from Jupiter during 1963 and 1964 demonstrate that many of the so-called bursts with quasiperiods of 1-10 sec are caused by the sweeping of an interplanetary diffraction pattern across the receiver by the motion of scattering irregularities in the solar wind. Measurements made on these scintillations include arrival time differences at spaced receivers, scintillation rate, angular position scintillation, and the width of the scattered angular power spectrum.The derived properties of the scattering irregularities are as follows. (1) The solar wind is radially directed with respect to the Sun and possesses an average velocity V s """ 600 km sec-i. (2) (6) The irregularities in electron density with dimensions of hundreds of kilometres are relatively weak (-10%) in oomparison with the average eleotron density.Theoretical restriotions on source size are used to derive an upper limit of -0·6 sec of arc to the angular diameter of the deoametrio source on Jupiter. It is shown that the intensity sointillations are significantly reduced when the line of sight pa.sses within 60° of the Sun; if this is due to the finite source size, a. lower limit of -0·1 sec of arc oan be assigned to the source diameter.. I. INTRODUOTION Shortly after the discovery of the Jovian decametric radio emission by Burke and Franklin (1955) it was realized that some, if not all, of the intensity variations may be imposed on an essentially steady intrinsic emission by propagation effects . between the planet and observer. Such considerations led Gardner and Shain (1958) to record bursts simultaneously at sites separated by 25 km, observations that showed the presence of considerable differences between the time variations at the two receivers. Subsequent spaced-receiver experiments by Smith et al. (1960) and Douglas and Smith (1961) over baselines varying in length from 15 to 7000 km showed that all degrees of burst correlation could be experienced; the differences were usually ascribed to the effects of ionospheric scintillations which, from discrete radio source observations, were known to be poorly correlated over distances greater than about 5 km.

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Section: (B) Angular Spectrum Of Scattered Radiationmentioning

confidence: 95%

Section: (B) Angular Spectrum Of Scattered Radiationmentioning

confidence: 98%

Section: (D) Intensity Fluctuations Across the Ground Planementioning

confidence: 99%

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The Solar Wind and Jovian Decametric Radio Emission

Slee¹,

Higgins²

1968

Aust. J. Phys.

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“…An analysis to do this was developed by Briggs et al (1950), Phillips and Spencer (1955), Ratcliffe (1956), and others and called the FCA method. A more contemporary description is given by Briggs (1984) and Holdsworth and Reid (1995a).…”

Section: Spaced Antenna Analysis Techniquesmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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The application of medium-frequency (MF) and high-frequency (HF) partial reflection radar to investigate the neutral upper atmosphere is one of the oldest such techniques still regularly in use. The techniques have been continuously improved and remain a robust and reliable method of obtaining wind velocities, turbulence intensities, electron densities, and measurements of atmospheric structure in the mesosphere lower thermosphere (MLT) region (50 to 110 km). In this paper, we review recent developments, discuss the strengths and weaknesses of the technique, and consider possible improvements.

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“…Much work has been done in attempting to account for the various features of the pattern by .considering a diffraction mechanism involving small-scale irregularities of ·electron densities in the ionosphere. This aspect of the work has been reviewed by Ratcliffe (1956).…”

Section: Introductionmentioning

confidence: 99%

A Study of Phase Fading of Ionospheric Reflections

Monro¹

1962

Aust. J. Phys.

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SummaryPulsed 2·28 Mc/s radio waves were transmitted imd measurements were made on the first-hop, vertically-incident reflections from the ionosphere. A method of continuously recording the changes of phase difference between the signals at two aerials is described. The general features of the records are described and it is shown that the quasi-periodic type of fading can be explained in terms of two component rays being reflected from two reflecting areas of the ionosphere and interfering at the receiving aerials. The horizontal separation of the two regions is about 50 km in the case analysed. The direction of arrival of the radio waves, the velocity of the amplitude pattern over the ground, and the statistical distribution of the phase difference are also discussed for this type of fading.

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Some Aspects of Diffraction Theory and their Application to the Ionosphere

Cited by 479 publications

References 39 publications

The Solar Wind and Jovian Decametric Radio Emission

The Solar Wind and Jovian Decametric Radio Emission

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

A Study of Phase Fading of Ionospheric Reflections

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