scholarly journals A Discussion of Ionospheric Demodulation Near Gyro Frequency

1959 ◽  
Vol 12 (2) ◽  
pp. 157 ◽  
Author(s):  
GL Goodwin
Keyword(s):  
Modulation Frequency ◽  
Wave Interaction ◽  
Radio Waves ◽  
Large Magnitude ◽  
Reflected Wave ◽  
Made In

Observations made in Adelaide of the ionospheric demodulation of radio waves near gyro frequency at vertical incidence are discussed. The effect occurs in the region of about 90 km, and does not appear to decrease through dawn. An F-Iayer reflected wave is demodulated by unequal amounts during its two passages through the region. The large magnitude of the effect and its lack of dependence on modulation frequency seem to be inconsistent with the theory of wave interaction.

scholarly journals The oblique reflexion of very long wireless waves from the ionosphere

1947 ◽  
Vol 189 (1016) ◽  
pp. 130-147 ◽  
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Theoretical Basis ◽  
Plane Waves ◽  
Angle Of Incidence ◽  
Vertical Magnetic Field ◽  
Radio Waves ◽  
Contour Integrals ◽  
General Terms ◽  
Made In

An attempt is made in the paper to provide a satisfactory theoretical basis for a future discussion of the experimental data on the propagation of very long radio waves (18,800 m.) given by Best, Ratcliffe & Wilkes, and Budden, Ratcliffe & Wilkes. The reflexion of very long plane waves incident obliquely on a horizontally stratified ionized medium with a vertical magnetic field is first considered in general terms, and it is shown that the medium can be divided into a transition region and a reflecting region. If the ionization in the reflecting region increases linearly with height it is shown that propagation is governed by the following equations: ∂ 2 L / ∂ζ 2 + (α + ζ) L + β M = 0, ∂ 2 M / ∂ζ 2 + (α - ζ) M + β L = 0, where α and β are constants depending on the angle of incidence. Under the conditions of the experiments β is small, and a solution, in terms of contour integrals, valid in this case is obtained.

scholarly journals A study of the interaction of radio waves

1948 ◽  
Vol 193 (1034) ◽  
pp. 311-343 ◽  
Keyword(s):  
Wave Interaction ◽  
The Other ◽  
Radio Waves ◽  
Absorption Process ◽  
Absorption Mechanism ◽  
Linear Absorption ◽  
Standard Nomenclature ◽  
Ionospheric Absorption ◽  
Series Of Experiments ◽  
Crucial Experiments

Experiments are described in which the phenomenon of wave-interaction (‘Luxembourg effect’) is used to provide information about the height at which radio waves of different frequencies are absorbed in the ionosphere. It is first, demonstrated by two crucial experiments that the absorption mechanism suggested by Bailey & Martyn (1934 a and b ) is the true one. Measurements of the phase of the modulation transferred from one wave to the other by the non-linear absorption process in the ionosphere are described; and it is shown how, by measuring this phase at different modulation frequencies, it is possible to locate the region where the interaction occurs. The results of a series of experiments summarized in tables 2, 3 a and 3 b and figures 8 and 9 are discussed. The conclusion is reached that the frequency with which electrons collide with neutral molecules at a height of about 85 km. is of the order 5 x 10 5 sec. -1 , and that this is the height near which the main absorption of waves of frequency 1 Mcyc./sec. and 200 kcyc./sec. are absorbed at night. Waves of frequency 90 and 68 kcyc./sec. are absorbed, and possibly also reflected, below this level. With the approach of dawn the regions responsible for absorbing 1 Mcyc./sec. and 200 kcyc./sec. waves drift apart. The theory of Bailey & Martyn (1934 b ) and Bailey (1937 a ) is related to modern theories of ionospheric absorption and is restated with the standard nomenclature of Appleton’s magneto-ionic theory.

scholarly journals Experimental and theoretical studies of the behaviour of slow electrons in air. II. Ionospheric and other applications

1949 ◽  
Vol 196 (1046) ◽  
pp. 427-435 ◽  
Keyword(s):  
Experimental Data ◽  
Free Electron ◽  
Laboratory Data ◽  
Wave Interaction ◽  
Theoretical Studies ◽  
Radio Waves ◽  
Electronic Motion ◽  
Slow Electrons ◽  
Experimental And Theoretical Studies

The significance, for ionospheric and other studies, of the experimental data given in part I is considered. It is shown how the data obtained from rocket soundings may be combined with the measurements of wave interaction in the ionosphere and the laboratory data given in part I, to estimate the height at which wave interaction occurs and the collisional frequency at that height. The following topics are also discussed: the theory of electronic motion in direct and alternating fields; the power communicated to a free electron in a gas by an alternating field; and the interaction of radio waves in the ionosphere.

The thermal self-focusing of a wave beam in an underdense plasma. Part 1. The wave spectrum

1983 ◽  
Vol 29 (2) ◽  
pp. 325-358 ◽  
Author(s):  
M. J. Giles
Keyword(s):  
Pump Wave ◽  
Wave Spectrum ◽  
Wave Interaction ◽  
Density Perturbation ◽  
Radio Waves ◽  
Side Band ◽  
Drift Motion ◽  
Ionospheric Modification ◽  
Thermally Driven ◽  
Underdense Plasma

The present series of papers is concerned with the problem of the thermal selffocusing of an electromagnetic wave in an underdense plasma which is examined within the context of ionospheric modification by high-power radio waves. We formulate this problem as a coherent four-wave interaction between a pump wave, Stokes side-band waves and a thermally driven density perturbation. Our treatment assumes that the heating of the electrons in the interference pattern of the pump and side-band waves is in equilibrium with longitudinal heat conduction and energy transfer to the ions and, in addition, that the density perturbation is subject to decay on account of longitudinal ambipolar diffusion, ambient plasma drift motion, recombination and the stabilizing influence of perturbations to the electrical conductivity.

Sir Edward Appleton and early ionosphere research

1997 ◽  
Vol 51 (2) ◽  
pp. 281-290 ◽  
Author(s):  
M. V. Wilkes
Keyword(s):  
Ionizing Radiation ◽  
Low Pressure ◽  
Conducting Layer ◽  
Radio Waves ◽  
Electric Currents ◽  
Earth’S Atmosphere ◽  
The Earth ◽  
Series Of Experiments ◽  
Second Wave ◽  
Made In

The earliest suggestion that there might be a conducting layer in the earth's atmosphere was made in 1839 by Gauss, who was concerned to explain the diurnal geomagnetic phenomena, and who pointed out that a possible hypothesis was that they arose from electric currents encircling the earth somewhere in the atmosphere. However, at that time, no mechanism to account for the existence of a conducting layer could be suggested, nor was there any knowledge of how air could become conducting; indeed, until ionizing radiation began to be studied, it was even suggested that air naturally became conducting at low pressure. It was soon apparent that the propagation of radio waves beyond the horizon could not be explained as the result of diffraction. Heaviside and Kennelly, at about the same time, both proposed that a conducting layer in the atmosphere was responsible. It was Appleton who first showed, by an elegant and well planned series of experiments, that this was indeed the case; or to put it more precisely, that at a point distant from the transmitter there was, in addition to a wave received along the surface of the earth, a second wave descending from the sky.

scholarly journals Strip Integration in Radio Astronomy

1956 ◽  
Vol 9 (2) ◽  
pp. 198 ◽  
Author(s):  
RN Bracewell
Keyword(s):  
Two Dimensional ◽  
Radio Waves ◽  
Cross Sectional ◽  
Principal Solution ◽  
Full Reconstruction ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Special Case ◽  
Made In ◽  
True Distribution

When a celestial source of radio waves is scanned with an aerial beam which is much longer than the source in one direction but suitably narrow in the other, the transformation from the true distribution to the measured value is referred to as strip integration. It is here treated as a special case of two-dimensional aerial smoothing in which the aerial beam is allowed to spin about its centre as it moves about the sky. It is shown that the resolution obtainable is set by the cross-sectional profile of the strip beam in the narrow dimension. Thus, when the strip reduces to a line, the resolution is complete and full reconstruction of the true distribution is possible; but scans must be made in all directions. In the general case it is shown that there is a principal solution, and that a finite number of scans suffices to determine it. A method is presented for reconstructing the principal solution from the observed data.

scholarly journals Managing the Adaptation of Modern Society to the Industry 4.0 Based on Information Waves and Impulses

2019 ◽  
Vol 8 (2) ◽  
pp. 438-446 ◽  
Author(s):  
Elena Popkova ◽  
Anastasia Sozinova ◽  
Vera Menshchikova
Keyword(s):  
Internal Structure ◽  
Industry 4.0 ◽  
Wave Interaction ◽  
Modern Society ◽  
Black Box ◽  
Management Process ◽  
Impulse Wave ◽  
The Media ◽  
Four Levels ◽  
Made In

The article analyzes the essence of the management process of adaptation of modern society to the industry 4.0 on the basis of information waves and impulses based on original ideas and scientific discoveries made in the article by A.P. Sukhodolov, I.V. Anokhov and V.A. Marenko Information impulse-wave interaction between the media and society. Scientists proposed an impulsive-oscillating mechanism for the influence of information on four levels of its perception by an individual to explain the essence, logic and internal structure of the management process of modern society's adaptation to the industry 4.0, traditionally represented in the form of an unexplained and little-studied “black box”. As a result, the authors have developed a mechanism for managing the adaptation of modern society to the industry 4.0 on the basis of information waves and pulses.

scholarly journals The characteristics of downcoming radio waves

1935 ◽  
Vol 148 (863) ◽  
pp. 104-120 ◽  
Keyword(s):  
Vertical Plane ◽  
Angle Of Incidence ◽  
Radio Waves ◽  
Lateral Deviation ◽  
Low Latitudes ◽  
Made In

In a recent paper Cherry and Martyn, from a study of the fading experienced simultaneously on a loop and vertical aerial, concluded that there was normally present a lateral deviation of the downcoming rays from the vertical plane through emitter and receiver. It is the main object of the present paper to examine this lateral deviation more completely, and to measure its amount. It has been noted by several workers that the measurement of the angle of incidence of downcoming rays by simultaneous observations on loop and aerial leads to results which vary markedly in periods of a few seconds, and are moreover inconsistent with those deduced from the heights of the reflecting regions in the ionosphere. These inconsistencies have been attributed by various authors to ( a ) “angle flicker” of the sky wave; ( b ) the purely geometrical consequence of lateral deviation of the sky wave; and ( c ) the fact that the measurements were made in low latitudes.

18-25 GHz low-noise Line Receiver for the Tidbinbilla 64-m Antenna

1981 ◽  
Vol 4 (2) ◽  
pp. 262-264 ◽  
Author(s):  
D. L. Jauncey ◽  
M. J. Batty ◽  
G. J. Gay ◽  
C. R. Moore ◽  
P. J. Batelaan ◽  
...  
Keyword(s):  
Spectral Line ◽  
Radio Astronomy ◽  
Low Noise ◽  
Present System ◽  
First Line ◽  
Deep Space Network ◽  
Beam Shape ◽  
Reflected Wave ◽  
Beam Switching ◽  
Made In

A K-band (18-25 GHz) reflected-wave ruby maser (Moore and Clauss 1979) has been borrowed from the National Radio Astronomy Observatory for radio astronomy use on the NASA 64-m antenna of the Deep Space Network at the Tidbinbilla Tracking Station, near Canberra. The purpose of the installation is to provide additional sensitive spectral line, continuum, and VLBI capabilities in the southern hemisphere. Previous measurements at 22.3 GHz (λ = 13.5 mm) determined that the Tidbinbilla 64-m antenna has a peak aperture efficiency of ˜22%, a well-behaved beam shape and consistent pointing (Fourikis and Jauncey 1979). Before installing the maser on the antenna a cooled (circulator) switch was added to provide a beam-switching capability, and a spectral line receiver following the maser was incorporated. The system was assembled and tested at JPL in late 1980 and installed at Tidbinbilla early in 1981. We give here a brief description and present some of the first line observations made in February and March 1981. Extensive line and continuum observations are planned with the present system and a program is under way to determine the telescope pointing characteristics.

The triple coalescence of coupling points for waves in stratified media

1994 ◽  
Vol 445 (1924) ◽  
pp. 257-272 ◽  
Keyword(s):  
Basic Theory ◽  
Stratified Medium ◽  
Phase Advance ◽  
Stratified Media ◽  
Radio Waves ◽  
Phase Retardation ◽  
Reflected Wave

For waves propagating in a plane stratified medium coupling between two characteristic waves occurs near points where the eigenvalues for the two waves are equal, and these are called coupling points. More complicated effects occur where two coupling points coincide. This is called a coalescence of coupling points. It has been previously studied for the case where the same pair of eigenvalues is equal at each of the coalescing coupling points. This paper studies the case where the equal eigenvalues at the two coupling points are not the same pair, but have one eigenvalue in common so that at the coalescence three eigenvalues are equal. This is called a triple coalescence and it can occur for radio waves in the ionosphere. The basic theory is given and tested by some computed solutions. It brings to light some cases where the expected ½π phase advance of a reflected wave is replaced by a ½π phase retardation. A possible generalization of the theory to deal with more complicated coalescences is briefly discussed.

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