Статті в журналах: "Radio waves (Theory)"

1

Apple, Jacki, Regine Beyer, and Richard Kostelanetz. "Making Radio Waves." TDR (1988-) 36, no. 2 (1992): 7. http://dx.doi.org/10.2307/1146189.

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2

Jones, W., and J. Jones. "Oblique scattering of radio waves from meteor trains: Theory." Planetary and Space Science 38, no. 1 (January 1990): 55–66. http://dx.doi.org/10.1016/0032-0633(90)90005-b.

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3

Gordon, W. E. "The Propagation of Radio Waves: The Theory of Radio Waves of Low Power in the Ionosphere and Magnetosphere." Eos, Transactions American Geophysical Union 68, no. 12 (1987): 164. http://dx.doi.org/10.1029/eo068i012p00164-03.

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4

Rycroft, M. J. "The Propagation of Radio Waves: the Theory of Radio Waves of Low Power in the Ionosphere and Magnetosphere." Physics of the Earth and Planetary Interiors 43, no. 3 (September 1986): 255–57. http://dx.doi.org/10.1016/0031-9201(86)90054-3.

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5

Heading, J. "The Propagation of Radio Waves—The Theory of Radio Waves of Low Power in the Ionosphere and Magnetosphere." Journal of Atmospheric and Terrestrial Physics 48, no. 4 (April 1986): 415–16. http://dx.doi.org/10.1016/0021-9169(86)90009-7.

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6

Yeang, Chen-Pang. "From Mechanical Objectivity to Instrumentalizing Theory: Inventing Radio Ionospheric Sounders." Historical Studies in the Natural Sciences 42, no. 3 (June 1, 2012): 190–234. http://dx.doi.org/10.1525/hsns.2012.42.3.190.

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While the discovery of the ionosphere through wireless communications technology in the mid-1920s had built a close connection between atmospheric science and radio, the full-fledged use of radio waves as a geophysical probe did not start until an instrumental development occurred a few years later. This article examines this advance, which centered on the invention of radio sounders of the ionosphere. Like the earlier radio experiments on the ionosphere, the sounders bounced radio waves off the upper atmosphere and inferred its properties from the returns. But the new apparatuses contained valuable innovations. In the 1930s, researchers at American Telephone and Telegraph Company (AT&T), Britain's Radio Research Board (RRB), the Technical University of Munich, and the U.S. National Bureau of Standards (NBS) automated data recording with oscilloscopic displays and inscription gadgets. They also devised control mechanisms to synchronize the acquisition of data with the change of transmitting signals. On the one hand, such automation was consistent with Lorraine Daston and Peter Galison's "mechanical objectivity," which minimizes human interference, makes experiments repeatable, and reduces personal equations, most notably perhaps with the Bureau of Standards' automatic single-frequency sounder. On the other hand, however, the automation also embodied mechanically theory-laden experimental procedures—it instrumentalized a theory that underlay the experimental scheme. The British and Americans' sweep-frequency recorder reckoned precisely the mandate of the magneto-ionic theory, the dominant model of radio-wave propagation. The sweep-frequency recorder incorporated the magneto-ionic theory by producing an easy-to-measure critical condition that the theory had predicted.

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7

Cairns, Iver H., P. A. Robinson, and G. P. Zank. "Progress on Coronal, Interplanetary, Foreshock, and Outer Heliospheric Radio Emissions." Publications of the Astronomical Society of Australia 17, no. 1 (2000): 22–34. http://dx.doi.org/10.1071/as00022.

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AbstractType II and III solar radio bursts are associated with shock waves and streams of energetic electrons, respectively, which drive plasma waves and radio emission at multiples of the electron plasma frequency as they move out from the corona into the interplanetary medium. Analogous plasma waves and radiation are observed from the foreshock region upstream of Earth's bow shock. In situ spacecraft observations in the solar wind have enabled major progress to be made in developing quantitative theories for these phenomena that are consistent with available data. Similar processes are believed responsible for radio emissions at 2–3 kHz that originate in the distant heliosphere, from where the solar wind interacts with the local interstellar medium. The primary goal of this paper is to review the observations and theories for these four classes of emissions, focusing on recent progress in developing detailed theories for the plasma waves and radiation in the source regions. The secondary goal is to introduce and review stochastic growth theory, a recent theory which appears quantitatively able to explain the wave observations in type III bursts and Earth's foreshock and is a natural theory to apply to type II bursts, the outer heliospheric emissions, and perhaps astrophysicalemissions.

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8

Canobbio, E., and R. Croci. "Space-dependent quasi-linear theory of lower-hybrid waves." Journal of Plasma Physics 46, no. 2 (October 1991): 347–64. http://dx.doi.org/10.1017/s0022377800016160.

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The quasi-linear diffusion coefficients for the inherently space-dependent wave amplitudes in lower-hybrid heating and current-drive experiments are derived and compared with the usual space-independent approximation. The distribution function is derived and the dependence on the radio-frequency field amplitude gradient of the ‘plateau’, which is an essential quantity in thetheoretical description of LH experiments, is stressed.

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9

Wilkie, Bill. "The Daintree Blockade: Making (radio) waves." Queensland Review 28, no. 2 (December 2021): 166–68. http://dx.doi.org/10.1017/qre.2022.13.

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Radio log 11/8/84D5 crossing creek under Timbertop’s tree … continues to fill the creek crossing … If he continues to fill it high enough the D10 should go through. Looks like a moonscape where the dozers are working.

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10

Schutz, Bernard F. "Astrometric and timing effects of gravitational waves." Proceedings of the International Astronomical Union 5, S261 (April 2009): 234–39. http://dx.doi.org/10.1017/s1743921309990457.

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AbstractGravitational wave detection can be done by precision timing of millisecond pulsars, and (with less likelihood) by precision astrometry on distant objects whose light or radio waves pass through gravitational waves on their way to our observatories. Underlying both of these is the relatively simple theory of light propagation in spacetimes with gravitational waves, which is also the basis of interferometric gravitational wave detectors. I review this theory and apply it to the timing and astrometric methods of detection. While pulsar timing might even be the first way that we directly detect gravitational waves, light deflection by gravitational waves seems out of reach.

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11

Fejer, J. A. "The Propagation of Radio Waves: The Theory of Radio Waves of Low Power in the Ionosphere and Magnetosphere (K. G. Budden)." SIAM Review 30, no. 2 (June 1988): 327. http://dx.doi.org/10.1137/1030067.

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12

You, Ben, Liang Zhou, Lin-Sheng Wu, Yao-Ping Zhang, and Jun-Fa Mao. "Theory of Reflective Phase-Shifting Surface for Generating Vortex Radio Waves." IEEE Transactions on Antennas and Propagation 64, no. 11 (November 2016): 4942–48. http://dx.doi.org/10.1109/tap.2016.2602371.

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13

Cairns, Iver H. "The Source of Free Energy for Type II Solar Radio Bursts." Publications of the Astronomical Society of Australia 6, no. 4 (1986): 444–46. http://dx.doi.org/10.1017/s1323358000018348.

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AbstractA theory for the source of free energy for the Langmuir waves producing Type II bursts is presented. It is shown that electrons accelerated at the Type II shock naturally develop a distribution function with an abrupt cutoff at a characteristic minimum parallel velocity (a ‘cutoff distribution) in a limited spatial volume ahead of the shock, irrespective of the acceleration process active at the shock. The long duration, narrow bandwidth Type II radiation is then explained in terms of Langmuir waves produced by a cutoff distribution. The theory also accounts in a natural way for split-band Type II bursts and herringbone bursts.

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14

Beskin, V. S., A. V. Gurevich, and Ya N. Istomin. "Some Aspects of Radio Pulsar Evolution." International Astronomical Union Colloquium 128 (1992): 39–41. http://dx.doi.org/10.1017/s0002731600154721.

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It is shown that pulsar statistics are in good agreement with the theory of current (plasma) energy losses of a neutron star. Up to now two theories of pulsar braking have been considered. The first well known model is connected with the radiation of vacuum magneto-dipole waves (Ostriker and Gunn 1969). However, according to the electrodynamical theory of pulsars, the presence of a rather dense plasma in the magnetosphere of a neutron star leads inevitably to a complete suppression of magneto-dipole losses—the dynamics of the stellar slow down is determined by the longitudinal current only (Beskin, Gurevich, and Istomin 1983).

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15

Zernov, N. N., M. A. Bisyarin, and V. E. Germ. "Diffraction Theory of Propagation of High-Frequency Radio Waves in a Spherically Layered Ionospheric Radio Channel." Радиотехника и электроника 68, no. 6 (June 1, 2023): 563–70. http://dx.doi.org/10.31857/s0033849423060189.

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A special analytical method is developed to describe the propagation of high-frequency electromagnetic waves emitted by a vertical point dipole from the surface of perfectly conducting Earth in a regular spherically layered background ionosphere. The basic representation of the wave field employs an integral over the set of wave components, each of which is related to a specific ray trajectory. Such an approach makes it possible to analytically take into account the effect of medium-scale 3D inclusions in the background ionosphere as an additional phase shift of the wave component with allowance for the distortion of its ray trajectory and to numerically calculate the effect of wave-field focusing.

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16

Zernov, N. N., M. A. Bisyarin, and V. E. Germ. "Diffraction Theory of Propagation of High-Frequency Radio Waves in a Spherically Layered Ionospheric Radio Channel." Journal of Communications Technology and Electronics 68, no. 6 (June 2023): 659–65. http://dx.doi.org/10.1134/s1064226923060189.

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17

Naylor, GRS, and RE Robson. "Interpretation of Backscattered HF Radio Waves from the Sea." Australian Journal of Physics 39, no. 3 (1986): 395. http://dx.doi.org/10.1071/ph860395.

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Radar oceanographers have long relied upon a simple diffraction grating model of the sea surface to explain the predominant features in the backscattered Doppler frequency spectrum. It is argued in this paper, however, that the ruled diffraction grating model with scattering localized to wave crests is incorrect and that a sinusoidal grating of period one-half the radio wavelength, with scattering from the entire surface, is the simplest representation of the sea surface which is consistent with both rigorous theory and experimental observation.

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18

Kincaid, Andrew. "Samuel Beckett's Radio Geographies." Modernist Cultures 17, no. 1 (February 2022): 54–73. http://dx.doi.org/10.3366/mod.2022.0359.

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Throughout his work, Samuel Beckett interrogates the idea that voice is an authentic conduit for identity. Radio distorts, edits, and projects speech, and so broadcasting was a natural choice for his lifelong experiment. Both objects – radio and voice – are also fundamentally spatial. They distribute waves of sound across a given terrain. Beckett's interest in radio is abstract, in that the medium allows him to investigate general concerns about the construction of subjectivity – the ways in which we are all subject to disparate voices. But the writer's engagement with radio also arises against the backdrop of specific material conditions in post-War France and Europe. These were the years that French spatial theory took up the problem of urban modernisation. Gaston Bachelard's Poetics of Space was published in 1957, the same year that Beckett wrote his first radio play, and also the same year that work began on Le Périphérique, Europe's first ring road. This paper investigates Beckett's radio plays against the backdrop of urban theory ( urbanisme), arguing that Beckett's work can reveal light on theories of space, even urban geography.

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19

Spangler, S. R. "Interstellar Magnetohydrodynamic Waves as Revealed by Radio Astronomy." Symposium - International Astronomical Union 140 (1990): 176. http://dx.doi.org/10.1017/s0074180900189880.

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The plasma density fluctuations responsible for interstellar scintillations occur on the same scales as interstellar magnetohydrodynamic waves (Alfvén waves), which are responsible for many important processes such as the acceleration of the cosmic rays. This suggests that these density fluctuations represent a compressive component of MHD waves, and raises the exciting possibility that radioastronomical observations can provide more or less direct measurements of interstellar microphysical processes. Extraction of MHD wave properties from the radio scattering measurements requires a sound theoretical understanding of the relationship between the magnetic field in an MHD wave and the corresponding plasma density perturbation. We present a plasma kinetic theory treatment of the density compression associated with an MHD wave field. The density perturbation may be expressed as the sum of three terms. These terms are proportional to the wave amplitude, wave intensity, and sine transform of the wave intensity, respectively. The coefficients of these three terms are functions of the plasma β, the electron-to-ion temperature ratio, and the angle of wave propagation with respect to the large scale magnetic field. This relation can serve as the basis for inferring the MHD wave field given a radio scattering measurement of the density fluctuation statistics. In an attempt to apply these ideas to the interstellar plasma turbulence, we have made VLBI angular broadening measurements of sources whose lines of sight pass close to supernova remnants. The intensity of MHD waves is expected to be high in the vicinity of the shock waves associated with supernova remnants. We do not yet have unambiguous evidence of enhanced radio wave scattering due to shock-associated MHD waves. However, we have found anomalously high scattering for the source CL4, whose line of sight passes through the Cygnus Loop.

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20

Carcione, José M. "Ground‐penetrating radar: Wave theory and numerical simulation in lossy anisotropic media." GEOPHYSICS 61, no. 6 (November 1996): 1664–77. http://dx.doi.org/10.1190/1.1444085.

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Subsurface georadar is a high‐resolution technique based on the propagation of high‐frequency radio waves. Modeling radio waves in a realistic medium requires the simulation of the complete wavefield and the correct description of the petrophysical properties, such as conductivity and dielectric relaxation. Here, the theory is developed for 2-D transverse magnetic (TM) waves, with a different relaxation function associated to each principal permittivity and conductivity component. In this way, the wave characteristics (e.g., wavefront and attenuation) are anisotropic and have a general frequency dependence. These characteristics are investigated through a plane‐wave analysis that gives the expressions of measurable quantities such as the quality factor and the energy velocity. The numerical solution for arbitrary heterogeneous media is obtained by a grid method that uses a time‐splitting algorithm to circumvent the stiffness of the differential equations. The modeling correctly reproduces the amplitude and the wavefront shape predicted by the plane‐wave analysis for homogeneous media, confirming, in this way, both the theoretical analysis and the numerical algorithm. Finally, the modeling is applied to the evaluation of the electromagnetic response of contaminant pools in a sand aquifer. The results indicate the degree of resolution (radar frequency) necessary to identify the pools and the differences between the anisotropic and isotropic radargrams versus the source‐receiver distance.

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21

Томилин, А. К., А. Ф. Лукин та А. Н. Гульков. "Эксперимент по созданию канала радиосвязи в морской среде". Письма в журнал технической физики 47, № 11 (2021): 48. http://dx.doi.org/10.21883/pjtf.2021.11.51009.18710.

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A full-scale experiment on the transmission of a short-wave modulated radio signal in a marine environment using spherical antennas at a distance of 470 m is described. The special transceiver equipment is designed in accordance with the results of the generalised electrodynamics theory. An assumption is made about the possibility of creating a high-frequency radio communication channel in the marine environment by means of longitudinal electromagnetic waves.

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22

Pirinen, Pekka, Harri Pennanen, Ari Pouttu, Tommi Tuovinen, Nuutti Tervo, Petri Luoto, Antti Roivainen, Aarno Pärssinen, and Matti Latva-aho. "RF Driven 5G System Design for Centimeter Waves." Wireless Communications and Mobile Computing 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/7852896.

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5G system design is a complex process due to a great variety of applications and their diverse requirements. This article describes our experiences in developing a centimeter waves mobile broadband concept satisfying future capacity requirements. The first step in the process was the radio channel measurement campaign and statistical modeling. Then the link level design was performed tightly together with the radio frequency (RF) implementation requirements to allow as large scalability of the air interface as possible. We started the concept development at 10 GHz frequency band and during the project World Radiocommunication Conference 2015 selected somewhat higher frequencies as new candidates for 5G. Thus, the main learning was to gain insight of interdependencies of different phenomena and find feasible combinations of techniques and parameter combinations that might actually work in practice, not only in theory.

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23

Azzollini, Francesco, A. Gordon Emslie, Daniel L. Clarkson, Nicolina Chrysaphi, and Eduard P. Kontar. "Plasma Motions and Compressive Wave Energetics in the Solar Corona and Solar Wind from Radio Wave Scattering Observations." Astrophysical Journal 968, no. 2 (June 1, 2024): 72. http://dx.doi.org/10.3847/1538-4357/ad4154.

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Abstract Radio signals propagating via the solar corona and solar wind are significantly affected by compressive waves, impacting the properties of solar bursts as well as sources viewed through the turbulent solar atmosphere. While static fluctuations scatter radio waves elastically, moving, turbulent, or oscillating density irregularities act to broaden the frequency of the scattered waves. Using a new anisotropic density fluctuation model from the kinetic scattering theory for solar radio bursts, we deduce the plasma velocities required to explain observations of spacecraft signal frequency broadening. The inferred velocities are consistent with motions that are dominated by the solar wind at distances ≳10 R ⊙, but the levels of frequency broadening for ≲10 R ⊙ require additional radial speeds ∼(100–300) km s−1 and/or transverse speeds ∼(20–70) km s−1. The inferred radial velocities also appear consistent with the sound or proton thermal speeds, while the speeds perpendicular to the radial direction are consistent with nonthermal motions measured via coronal Doppler-line broadening, interpreted as Alfvénic fluctuations. Landau damping of parallel propagating ion-sound (slow MHD) waves allows an estimate of the proton heating rate. The energy deposition rates due to ion-sound wave damping peak at a heliocentric distance of ∼(1–3) R ⊙ are comparable to the rates available from a turbulent cascade of Alfvénic waves at large scales, suggesting a coherent picture of energy transfer, via the cascade or/and parametric decay of Alfvén waves to the small scales where heating takes place.

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24

Li, Xiang Jiang, and Jing Fan. "Characteristics of Electromagnetic Waves Propagation in Corridor for High-Rise Buildings." Advanced Materials Research 490-495 (March 2012): 1278–83. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.1278.

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With the popularity of wireless communication systems, the question of radio signal coverage is getting more and more attentions in corridor for high-rise buildings. Using loss rectangular dielectric waveguide theory, the attenuation of electromagnetic wave transmission rate is calculated in theory. Because of the complexity of electromagnetic waves propagation conditions, site measurement of transmission loss is done in band 210MHz, 460MHz, 1.2GHz and 2.0GHz. Measurement results show that the wireless signal transmission loss rate is similar with the calculation of loss rectangular dielectric waveguide theory on the trend

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25

Mordachev, V. I. "FREQUENCY-INDEPENDENT LIMITS OF VALUES OF SYSTEM PARAMETERS OF CELLULAR COMMUNICATIONS AT MULTIPATH PROPAGATION OF RADIO WAVES IN URBAN AREA." Doklady BGUIR, no. 7-8 (December 29, 2019): 117–24. http://dx.doi.org/10.35596/1729-7648-2019-126-8-117-124.

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The analysis was carried out in order to clarify the estimates of the expected restrictions on characteristics of new-generation mobile communications (4G, 5G) under the existing restrictions on radiated power of subscriber radio equipment, as well as in conditions where the boundaries of urban sites are outside of the area of free radio waves propagation (RWP) between subscriber and base stations. Analysis was performed using the basic principles and ensemble models of statistical theory of electromagnetic environment, as well as the basic principles of information theory that determines the radio channel capacity in presence of interference. Frequency-independent relationships have been obtained for estimating a number of system parameters of cellular communications under the conditions of multipath RWP in urban canyons and the presence of internal system interference: estimation the required equivalent isotropic radiated power (EIRP) of subscriber stations, the maximum data transmission capacity of the backward radio channel, the maximum distance of qualitative communication, and also the permissible level of internal radio interference at given requirements for communication range, and the information transfer rate of reverse radio channel taking into account the accepted restrictions on EIRP of subscriber radio equipment. The obtained relations allowus to estimate the limits of possible values of these system parameters of modern and future mobile communications; these relations also provide the opportunity to justify the quality requirements for ensuring the intra-system electromagnetic compatibility at the required data rate in backward radio channels of cellular networks and the existing restrictions on EIRP of subscriber stations.

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26

Craddock, G. G., and P. H. Diamond. "Theory of shear suppression of edge turbulence by externally driven radio-frequency waves." Physical Review Letters 67, no. 12 (September 16, 1991): 1535–38. http://dx.doi.org/10.1103/physrevlett.67.1535.

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27

Bordo, V. G. "Self-excitation of radio waves in the metal–insulator–metal structure doped with metal nanowires." Journal of Applied Physics 133, no. 1 (January 7, 2023): 014301. http://dx.doi.org/10.1063/5.0127049.

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The effect of self-excitation of radio waves in the metal–insulator–metal structure doped with metal nanowires is predicted and its theory is developed. Both the transient stage of self-excitation and the steady-state regime of self-oscillation are analyzed in a fully analytical form. The numerical estimates demonstrate that this effect can be used for diverse practical purposes, in particular, for radio frequency wireless power harvesting. These findings extend the approach developed in nano-optics to the field of electrical engineering.

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28

Fujimoto, M., and T. Sawa. "Large-Scale Galactic and Intergalactic Magnetic Fields." Symposium - International Astronomical Union 140 (1990): 90–94. http://dx.doi.org/10.1017/s0074180900189648.

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Large-scale axisymmetric and bisymmetric spiral (ASS and BSS) structures are found of magnetic fields in spiral galaxies by measuring the Faraday rotation of polarized radio emission. Dynamo theory is introduced to explain the field structures, and strong magnetogravitational interaction is suggested to occur between the BSS magnetic fields and spiral density waves. Up-to-date data about the rotation measures RM and redshifts z of QSOs and distant radio galaxies are given for discussing large-scale intergalactic magnetic fields.

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29

Charnley, John. "Presidential Address: Navigation Aids to Aircraft All-weather Landing." Journal of Navigation 42, no. 2 (May 1989): 161–86. http://dx.doi.org/10.1017/s0373463300014405.

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1. INTRODUCTION. In his Presidential address last year J. E. D. Williams treated us to a most absorbing, largely philosophical review of the development of the science of navigation over the last five centuries. In discussing the profound and enduring influence of radio waves on air navigation over the last century he commended as of ‘transcending importance’ the ‘homing quality’ of the radio beam in which the accuracy increases as distance from the transmitter decreases. He illustrated this ‘homing quality’ with references to the radio range for en-route navigation and the instrument landing system (ILS) for guidance to the runway. But he went further and remarked ‘Automatic landings in regular airline service are an example of how a perceived potential of the homing quality of radio has drawn to navigation a whole range of diverse applied sciences including, in this case, information theory, the properties of semi-conductors and the theory of servomechanisms and control, among many others.’

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30

Simunin M. M. "Critical analysis of the work "Experiment to create a radio communication channel in the marine environment"." Technical Physics Letters 48, no. 14 (2022): 3. http://dx.doi.org/10.21883/tpl.2022.14.52065.18935.

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The article "Experiment to create a radio communication channel in the marine environment" (authors: A.K. Tomilin, A.F. Lukin, A.N. Gulkov) published in Journal "Technical Physics Letters" (2021, vol. 47, Issue 11) is analyzed from the standpoint of classical physics. The organization of the experiment in the mentioned publication, interpretation of its results, and theory underlying the work are criticized. The proposed material is a methodological commentary and is intended to form consistent approaches to be used in studying and interpreting further works on creation of radio communication channels. Keywords: Radio communication in the marine environment, electromagnetic waves, methodological notes

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31

Machabeli, George Z. "The Mechanisms for the Generation of Pulsar Radio and High-energy Emission." Publications of the Astronomical Society of Australia 18, no. 4 (2001): 394–99. http://dx.doi.org/10.1071/as01045.

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AbstractThe recent theory of propagation and generation of waves in a pulsar’s magnetosphere is discussed. In particular we consider models of pulsar radio emission due to plasma instabilities. Wave–particle interactions can lead to quasilinear diffusion increasing a particle’s pitch-angle. The recent model of γ-ray emission from synchrotron radiation as a result of quasilinear diffusion is discussed.

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32

Ostashev, Vladimir E., Daniel J. Breton, and D. Keith Wilson. "Interference of the direct and ground-reflected waves in the atmosphere with volumetric scattering." Journal of the Acoustical Society of America 156, no. 1 (July 1, 2024): 107–18. http://dx.doi.org/10.1121/10.0026452.

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The interference of the direct and ground-reflected sound waves is significantly affected by volumetric scattering in the atmosphere, such as scattering by turbulence and forest. In the present article, the existing theory describing this interference is generalized to three somewhat independent but equally important cases. First, the attenuation of the direct and ground-reflected waves caused by backscattering is addressed. Second, the existing theory is extended for statistically quasi-homogeneous turbulence in which the variances and length scales of the temperature and wind velocity fluctuations depend on the height above the ground. Third, the existing theory, which was previously formulated only for near-horizontal sound propagation, is generalized to slanted sound propagation as pertinent to elevated sound sources. Numerical results for slanted propagation demonstrate that atmospheric turbulence can significantly increase the sound pressure level at the interference minima. The extended theory of the interference of the direct and ground-reflected waves in the atmosphere with volumetric scattering is important for practical applications, such as auralization of flying aircraft and sound propagation in a forest, and can be adapted to radio wave propagation.

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33

Zhang, Yiteng. "Research on the classifications of gravitational wave." Theoretical and Natural Science 11, no. 1 (November 17, 2023): 150–54. http://dx.doi.org/10.54254/2753-8818/11/20230396.

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In daily life, we can transmit and obtain information through mechanical waves and electromagnetic waves. For example, judging where the fish swims from the flooded water waves, and learns from the wonderful music to know what kind of instrument the musicians are playing and communicating through the radio waves. Gravitational waves, a fundamental prediction of Einstein's theory of general relativity, have revolutionized our understanding of the universe. This essay explores the background of research on gravitational waves, tracing their theoretical origins to the early 20th century and highlighting their recent detection in 2015. The research technique employed involves highly sensitive interferometers, such as LIGO and Virgo, which can detect the minuscule distortions in space-time caused by these elusive waves. By observing the gravitational waves emitted during cataclysmic cosmic events, scientists can now delve deeper into the nature of black holes, neutron stars, and the origin of our universe. In conclusion, the discovery of gravitational waves opens up new avenues for exploring the cosmos, providing unprecedented insights into the fabric of space-time itself.

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34

SCHLICKEISER, R., and I. LERCHE. "Relations between interstellar density and magnetic field fluctuations I. Kinetic theory of fluctuations." Journal of Plasma Physics 68, no. 3 (April 2002): 191–202. http://dx.doi.org/10.1017/s0022377802001915.

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Using linear kinetic plasma theory the relation between electron density and magnetic field fluctuations for low-frequency plasma waves for Maxwellian background distribution functions of arbitrary temperatures in a uniform magnetic field is derived. By taking the non-relativistic temperature limit this ratio is calculated for the diffuse intercloud medium in our Galaxy. The diffuse intercloud medium is the dominant phase of the interstellar medium with respect to radio wave propagation, dispersion and rotation measure studies. The differences between the relation of electron density and magnetic field fluctuations from the linear kinetic theory compared with the classical magnetohydrodynamics theory are established and discussed.

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35

Соловьев, М. В., А. Г. Серегин, and Ю. Б. Иванов. "FEATURES OF CONSIDERATION OF ELECTROMAGNETIC WAVES AS A RAYLEIGH PROCESS." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 1 (March 10, 2023): 88–93. http://dx.doi.org/10.36622/vstu.2023.19.1.014.

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поставлен вопрос подробного описания областей теории электрической связи, распределение параметров в которых отличается от «обычного», наиболее часто встречаемого во всех областях науки распределения – гауссовского (нормального), приведены не только причины подобного отклонения от привычной картины, но и математическая формализация. Ввиду сложности рассмотрения вопроса в целом показывается только распределение Рэлея и, как вырожденный случай – распределение Райса. Помимо физических процессов описан применяемый математический аппарат из области математической статистики и высшей математики, введены применяемые термины, подготовлена теоретическая база, позволяющая погрузиться в рассматриваемую тематику даже слабо подготовленному читателю. В ходе исследования приводится общая информация о теории электрической связи, распространении радиоволн и статистической радиотехнике. Исследованы варианты принимаемых ЭМВ и особенности распределения их характеристик. Объектом исследования является распределение амплитудных и частотных характеристик принимаемых волн, предметом - особенности принимаемых волн с учетом искажения в канале связи. Тема исследования имеет междисциплинарный характер и предполагает привлечение источников как из сферы теории электрической связи, так и теории вероятностей и математической статистики we raised the question of a detailed description of the areas of the theory of electrical communication, the distribution of parameters in which differs from the “usual” distribution most often encountered in all fields of science - the Gaussian (normal) distribution, not only the reasons for such a deviation from the usual picture are given, but also mathematical formalization. Due to the complexity of considering the issue as a whole, we shown only the Rayleigh distribution and, as a degenerate case, the Rice distribution. In addition to physical processes, we described the applied mathematical apparatus from the field of mathematical statistics and higher mathematics, the terms used are introduced, a theoretical base is prepared that allows even a poorly prepared reader to immerse themselves in the subject under consideration. The study provides general information about the theory of electrical communication, propagation of radio waves and statistical radio engineering. We investigated variants of received EMW and features of distribution of their characteristics. The object of the study is the distribution of the amplitude and frequency characteristics of the received waves, the subject is the features of the received waves, taking into account the distortion in the communication channel. The research topic is interdisciplinary in nature and involves the involvement of sources from both the theory of electrical communication and the theory of probability and mathematical statistics

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36

Kominis, Y., A. K. Ram, and K. Hizanidis. "Quasilinear theory of electron transport by radio frequency waves and nonaxisymmetric perturbations in toroidal plasmas." Physics of Plasmas 15, no. 12 (December 2008): 122501. http://dx.doi.org/10.1063/1.3029736.

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37

Robinson, P. A., I. H. Cairns, and D. A. Gurnett. "Clumpy Langmuir waves in type III radio sources - Comparison of stochastic-growth theory with observations." Astrophysical Journal 407 (April 1993): 790. http://dx.doi.org/10.1086/172560.

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38

Suchy, Kurt. "Theory of high-frequency (HF) radio waves in the second half of the 20th century." Journal of Atmospheric and Solar-Terrestrial Physics 62, no. 17-18 (November 2000): 1683–87. http://dx.doi.org/10.1016/s1364-6826(00)00120-6.

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39

Brophy, Thomas G., and Paul A. Rosen. "Density waves in Saturn's rings probed by radio and optical occultation: Observational tests of theory." Icarus 99, no. 2 (October 1992): 448–67. http://dx.doi.org/10.1016/0019-1035(92)90160-9.

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40

Tasnim, Samira, Gary P. Zank, Iver H. Cairns, and L. Adhikari. "Density Turbulence and the Angular Broadening of Outer Heliospheric Radio Sources at High Latitudes and in the Ecliptic Plane." Astrophysical Journal 928, no. 2 (March 31, 2022): 125. http://dx.doi.org/10.3847/1538-4357/ac5031.

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Abstract Density irregularities are responsible for the scattering of radio waves in the solar wind and astrophysical plasmas. These irregularities significantly affect the inferred physical properties of radio sources, such as size, direction, and intensity. We present here a theory of angular broadening due to the scattering of radio waves by density irregularities that improves the existing formalism used to investigate radio wave scattering in the outer heliosphere and the very local interstellar medium. The model includes an inner scale and both latitudinal and radial dependencies for the density fluctuation spectra and propagation paths for the radiation both near and out of the ecliptic plane. Based on the pickup-ion-mediated solar wind model (PUI model) of Zank et al., we estimate the turbulence and solar wind quantities for the high-latitude fast solar wind. The predictions include the density variance, inner/dissipation scale, velocity correlation length, mean magnetic field, and proton temperature. The density turbulence amplitude is estimated in two ways. First, a simple scaling technique is used to extend the theoretical predictions of the PUI model for the high-latitude wind beyond the heliospheric termination shock. Second, the solar wind and turbulence quantities are calculated near the ecliptic plane using plasma and magnetometer data from the Voyager 2 spacecraft over the period 1977–2018. Based on the turbulence models and observations, we calculate the scattering angle of the radio sources in the high-latitude and near-ecliptic wind. Finally, we compare the numerical results with the analytic predictions from Cairns and Armstrong et al. and the observed source sizes.

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41

Little, Reginald B. "Nano-Domains of Nuclear Magnetic Moments for Gravitational Stimulation of Biological Processes." European Journal of Applied Physics 4, no. 2 (March 28, 2022): 14–24. http://dx.doi.org/10.24018/ejphysics.2022.4.2.156.

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The recent theory of divergent integrations and divergent differentiations of superluminous spaces for new calculus of the objects for applications for new theory for the mechanics of gravity and the coupling of gravity to electromagnetic fields is applied here to recent data for the zero-gravity altering the biological processes of polymerase proteins replicating DNA for inducing misreadings and mistakes during reproduction for gravity affecting life and cancer. This paper presents new mode for coupling classical to quantum mechanics by gravity. The gravitational stimulating nuclei, hadrons and leptons for hidden drive of dynamics in matter for causing life is outlined. Alterations of gravity and relative motions for altering these dynamics for disease are shortly reviewed. The irrational, fractional superluminous nature of gravity is shown to manifest its nature and action; the distinct coupling of null NMMs relative to nonzero NMMs is given and moreover the different couplings of positive and negative NMMs and combinations thereof are given. The 1H, 14N, and 31P stable isotopes and the almost 100% relative abundances of their positive NMMs are noted to play roles in the origin and development of life and the manifestation of life by the action of gravity on these nano-domains of nonzero NMMs for manifesting ferromagnetism for all positive or all negative NMMs and/or antiferromagnetic and ferrimagnetism of mixed positive and negative NMMs. The uniquenesses of the second-row elements for life and hydrogen are considered. New phenomena by radio waves and the NMMs in elements of heaters and radio wave sources are considered and possibility of life creating radio waves. Some use of this theory for gravity upon nano-domains of NMMs for modeling many systems are noted.

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42

Enjie, Ding, Zhao Duan, and Li Xiao. "Research on the Radio Waves Propagation in Complex Coal Mine Workface." Intelligent Automation & Soft Computing 17, no. 8 (January 2011): 1113–23. http://dx.doi.org/10.1080/10798587.2011.10643215.

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43

Kulikov, G. V., Yu A. Polevoda, and M. S. Kostin. "Use of a spatially distributed in-phase antenna to increase the noise immunity of signal reception." Russian Technological Journal 11, no. 6 (December 14, 2023): 39–46. http://dx.doi.org/10.32362/2500-316x-2023-11-6-39-46.

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Objectives. Radio-technical information transmission systems are widely used in various sectors of our life, not only for telecommunications and associated domestic needs, but also for the functioning of various special services, such as emergency response units, which increasingly use robotic complexes in the course of their work. In the event of an emergency, robot devices can be used to get in under rubble, in concrete pipes or other municipal facilities, which typically result in a sharp deterioration of the necessary conditions for the propagation of radio waves. In this regard, the problem of ensuring reliable communication with the robotic complex becomes rather acute. The aim of the present work is to reduce the effect of multipath propagation of radio waves in the communication channel under complex interference conditions.Methods. The methods of statistical radio engineering and mathematical modeling are used according to optimal signal reception theory.Results. The presented model for a multi-element, spatially-distributed, in-phase receiving antenna of various configurations, featuring an electronically adjustable radiation pattern, is designed to ameliorate the multipath nature of signal propagation. A simulation of a multipath communication channel was carried out in the presence of one main and three reflected beams of radio wave propagation, as well as with harmonic interference at two angles of its arrival and different frequency detuning relative to the frequency of the useful signal. The probability of a bit error when receiving discrete information using the proposed antenna is estimated.Conclusions. The proposed signal processing algorithm on the receiving side can be used to partially compensate for the influence of the multipath effect. As a result, the noise immunity of information reception in comparison with reception on an omnidirectional antenna with one antenna element increases: for a bit error probability of 10−3, the energy gain ranges from 2 dB for two beams to 7–10 dB for three or four beams. In the presence of concentrated harmonic interference in the radio channel, its simultaneous spatial (by the antenna) and spectral (by the demodulator) filtering is also observed, the effectiveness of which depends on the direction of arrival and the frequency detuning of the interference, which also leads to a significant decrease in the error probability.

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44

Ghosh, Arka, Daniel Kagan, Uri Keshet, and Yuri Lyubarsky. "Nonlinear Electromagnetic-wave Interactions in Pair Plasma. I. Nonrelativistic Regime." Astrophysical Journal 930, no. 2 (May 1, 2022): 106. http://dx.doi.org/10.3847/1538-4357/ac581d.

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Abstract High brightness-temperature radiation is observed in various astrophysical sources: active galactic nuclei, pulsars, interstellar masers, and flaring stars; the discovery of fast radio bursts renewed interest in the nonlinear interaction of intense radiation with plasma. In astronomical systems, the radiation frequency is typically well above the plasma frequency and its spectrum is broad, so nonlinear processes differ considerably from those typically studied in laboratory plasma. This paper is the first in a series devoted to the numerical study of nonlinear interactions of electromagnetic waves with plasma. We start with nonmagnetized pair plasmas, where the primary processes are induced (Compton) scattering and filamentation instability. In this paper, we consider waves in which electron oscillations are nonrelativistic. Here, the numerical results can be compared to analytical theory, facilitating the development of appropriate numerical tools and framework. We distill the analytic theory, reconciling the plasma and radiative transfer pictures of induced scattering and developing in detail the kinetic theory of modulation/filamentation instability. We carry out homogeneous numerical simulations using the particle-in-cell codes EPOCH and Tristan-MP for both monochromatic waves and wave packets. We show that simulations of both processes are consistent with theoretical predictions, setting the stage for analyzing the highly nonlinear regime.

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45

Farrell, W. M., S. A. Curtis, M. D. Desch, and R. P. Lepping. "A theory for narrow-banded radio bursts at Uranus: MHD surface waves as an energy driver." Journal of Geophysical Research 97, A4 (1992): 4133. http://dx.doi.org/10.1029/91ja03143.

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46

Chian, Abraham C. L., Erico L. Rempel, and Félix A. Borotto. "Chaotic temporal variations in cosmic masers." Symposium - International Astronomical Union 206 (2002): 492–95. http://dx.doi.org/10.1017/s0074180900222924.

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Electron cyclotron maser emission is an accepted physical mechanism for generating coherent planetary and stellar radio emissions. Observational data has indicated evidence of nonlinear and chaotic temporal variability in some cosmic masers such as solar microwave spikes. The nonlinear and chaotic characteristics of cosmic masers can be attributed to plasma turbulence, such as Alfvén chaos, embedded in the emission region. We report a chaos theory of Alfvén waves which can account for chaotic acceleration of electrons in the source region of cosmic masers. Two types of Alfvén intermittency are identified: Pomeau-Manneville intermittency and crisis-induced intermittency. Since Alfvén waves may be responsible for accelerating electrons that emit maser radiations, the chaotic dynamics of Alfvén waves may be the origin of chaotic time variations of cosmic masers. Hence, we suggest that Alfvén intermittency may cause intermittent temporal fluctuations which can be observed in cosmic masers.

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47

Li, Yan, and Wen Bin Zhang. "Research on the Shielding Performance of Electromagnetic Shielding Clothes." Advanced Materials Research 150-151 (October 2010): 194–97. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.194.

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Electromagnetic shielding clothes for protecting human exposure from harmful radio waves have been commercialized. However, most research has so far focused on the fabrics. In this paper, based on the orthogonal experiment method, design the structure of the electromagnetic shielding clothes, and conduct the performance test. Through direct and variance analysis, find out the significance degree of the structure factors, and then get the best level combination of the factors, thus provide a theory basis for optimization structure design of electromagnetic shielding clothes.

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48

Manthei, Alina C., Jan Benáček, Patricio A. Muñoz, and Jörg Büchner. "Refining pulsar radio emission due to streaming instabilities: Linear theory and PIC simulations in a wide parameter range." Astronomy & Astrophysics 649 (May 2021): A145. http://dx.doi.org/10.1051/0004-6361/202039907.

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Context. Several important mechanisms that explain coherent pulsar radio emission rely on streaming (or beam) instabilities of the relativistic pair plasma in a pulsar magnetosphere. However, it is still not clear whether the streaming instability by itself is sufficient to explain the observed coherent radio emission. Due to the relativistic conditions that are present in the pulsar magnetosphere, kinetic instabilities could be quenched. Moreover, uncertainties regarding specific model-dependent parameters impede conclusions concerning this question. Aims. We aim to constrain the possible parameter range for which a streaming instability could lead to pulsar radio emission, focusing on the transition between strong and weak beam models, beam drift speed, and temperature dependence of the beam and background plasma components. Methods. We solve a linear relativistic kinetic dispersion relation appropriate for pulsar conditions in a more general way than in previous studies, considering a wider parameter range. In doing so, we provide a theoretical prediction of maximum and integrated growth rates as well as of the fractional bandwidth of the most unstable waves for the investigated parameter ranges. The analytical results are validated by comparison with relativistic kinetic particle-in-cell (PIC) numerical simulations. Results. We obtain growth rates as a function of background and beam densities, temperatures, and streaming velocities while finding a remarkable agreement of the linear dispersion predictions and numerical simulation results in a wide parameter range. Monotonous growth is found when increasing the beam-to-background density ratio. With growing beam velocity, the growth rates firstly increase, reach a maximum and decrease again for higher beam velocities. A monotonous dependence on the plasma temperatures is found, manifesting in an asymptotic behaviour when reaching colder temperatures. A simultaneous change of both temperatures proves not to be a mere linear superposition of both individual temperature dependences. We show that the generated waves are phase-coherent by calculating the fractional bandwidth. Conclusions. Plasma streaming instabilities of the pulsar pair plasma can efficiently generate coherent radio signals if the streaming velocity is ultra-relativistic with Lorentz factors in the range 13 < γ < 300, if the background and beam temperatures are small enough (inverse temperatures ρ0; ρ1 ≥ 1, i.e., T0; T1 ≤ 6 × 109), and if the beam-to-background plasma density ratio n1/(γbn0) exceeds 10−3, which means that n1/n0 has to be between 1.3 and 20% (depending on the streaming velocity).

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49

Brugarolas-Ortiz, Elena, Ignacio Rodríguez-Rodríguez, José-Víctor Rodríguez, Leandro Juan-Llácer, and Domingo Pardo-Quiles. "Using the Uniform Theory of Diffraction to Analyze Radio Wave Propagation along Urban Street Canyons for Device-to-Device Communication." Electronics 12, no. 3 (January 25, 2023): 593. http://dx.doi.org/10.3390/electronics12030593.

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This paper examines the propagation of radio waves in so-called urban street canyons through formulations based on Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD). As this type of environment comprises a street flanked by tall buildings more or less equally spaced on both sides (creating a canyon-like morphology), estimating the attenuation that radio signals may experience in these scenarios is crucial to the planning of urban device-to-device (D2D) wireless communication. In this sense, the results obtained through the analysis based on GO/UTD (in the horizontal plane containing the transmitter and receiver) are validated by a comparison with experimental measurements, showing good agreement. This work demonstrates how the use of GO/UTD-based formulations can contribute to a simpler and computationally more efficient planning of D2D mobile communication systems in which the considered propagation environment can be modeled as an urban street canyon comprising rectangular and equispaced buildings.

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50

McCann, BT, and RE Robson. "Scattering of HF Radio Waves from the Sea: A Review of the Theory Based upon a Simplified Model." Australian Journal of Physics 44, no. 5 (1991): 459. http://dx.doi.org/10.1071/ph910459.

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A simplified, physically intuitive model of diffuse scattering of radio waves from a rough surface is used to present a self-contained derivation of first- and second-order cross sections, essentially in agreement with the standard expressions. Incoherent addition of the second-order contributions (electromagnetic and hydrodynamic) leads to a cross section which is slightly different from the more rigorously derived cross sections of Barrick (1972b) and Johnstone (1975). A surface current v has been incorporated in this model, with the main change to the cross section being a frequency shift of the entire spectrum by an amount Llw = -2ko . v.

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