Incoherent Scattering of Radio Waves by Free Electrons with Applications to Space Exploration by Radar

1958 ◽  
Vol 46 (11) ◽  
pp. 1824-1829 ◽  
Author(s):  
W. Gordon
Keyword(s):  
Space Exploration ◽  
Incoherent Scattering ◽  
Radio Waves ◽  
Free Electrons

A theory of incoherent scattering of radio waves by a plasma

1960 ◽  
Vol 259 (1296) ◽  
pp. 79-99 ◽  
Keyword(s):  
Cross Section ◽  
Thermal Fluctuations ◽  
Incoherent Scattering ◽  
Doppler Broadening ◽  
Radio Waves ◽  
Central Frequency ◽  
Resonance Effects ◽  
Doppler Shifts ◽  
The Mean ◽  
Free Plasma

A theory is developed which describes the scattering of radio waves by the random thermal fluctuations of electron density in a collision-free plasma. The frequency spectrum, as well as the amplitude, of the scattered radiation is calculated. Particular attention is paid to the part of the spectrum which corresponds to small Doppler shifts, this being the region of greatest significance in connexion with the phenomenon of incoherent scattering from the ionosphere. The calculations are based on a generalized version of Nyquist’s noise theorem, and they lead to the following conclusions: (1) The mean scattering cross-section for the ionosphere is equal to that which would exist if each of the electrons scattered independently with a cross-section of one-half the classical Thomson cross-section. (2) The mean Doppler broadening of the scattered signal corresponds roughly to the speed of the ions rather than to that of the electrons. (3) The spectral shape of this signal is not Gaussian. There is a mild maximum in the spectrum away from the central frequency, as can be seen in figure 1. (4) Plasma resonance effects contribute only negligibly to the scattering for frequencies currently of interest.

Sir Granville Beynon, C. B. E.. 24 May 1914–11 March 1996

1998 ◽  
Vol 44 ◽  
pp. 53-62
Author(s):  
L. Thomas
Keyword(s):  
National Physical Laboratory ◽  
University Education ◽  
Major Influence ◽  
Radio Waves ◽  
Free Electrons ◽  
Physical Laboratory ◽  
Science And Education ◽  
The Many ◽  
The University ◽  
Happy Family

From his appointment as a Scientific Officer at the Radio Division of the National Physical Laboratory in 1938, which marked the start of his active collaboration with Sir Edward Appleton, to his death in 1996, Granville Beynon's chosen field of scientific endeavour was the study of the ionosphere, the atmosphere at heights where the concentration of free electrons is sufficient to influence the propagation of radio waves. Through his establishment of research groups at Swansea and Aberystwyth Colleges of the University of Wales, and his tenure of senior offices in appropriate national and international committees, he had a major influence in this area of science. His involvement in university education included a period as Vice–Principal at Aberystwyth, but his interest in education extended beyond the university sector and this was marked by his service as Chairman of the Schools Council Committee for Wales. For his services to science and education he received several honours at both national and international levels. In spite of the many demands on his time, he enjoyed a very happy family life in which music played a central part.

scholarly journals A mathematical model for DNA

2017 ◽  
Vol 14 (11) ◽  
pp. 1750152 ◽  
Author(s):  
Alireza Sepehri
Keyword(s):  
Mathematical Model ◽  
Radio Waves ◽  
Dna Molecules ◽  
Free Electrons ◽  
Men And Women ◽  
Dna Molecule ◽  
Electromagnetic Signals ◽  
M Theory ◽  
Bound Electrons ◽  
Damaged Dna

Recently, some authors have shown that a DNA molecule produces electromagnetic signals and communicates with other DNA molecules or other molecules. In fact, a DNA acts like a receiver or transmitter of radio waves. In this paper, we suggest a mathematical model for the DNA molecule and use of its communication to cure some diseases like cancer. In this model, first, by using concepts from string theory and M-theory, we calculate the energy of a DNA in terms of interactions between free electrons and bound electrons. We show that when a DNA is damaged, its energy changes and an extra current is produced. This extra current causes the electromagnetic signals of a damaged DNA molecule to be different when compared to the electromagnetic signals of a normal DNA molecule. The electromagnetic signals of a damaged DNA molecule induce an extra current in a normal DNA molecule and lead to its destruction. By sending crafted electromagnetic signals to normal DNA molecules and inducing an opposite current with respect to this extra current, we can prevent the destruction of normal DNA. Finally, we argue that the type of packing of DNA in chromosomes of men and women is different. This causes radiated waves from DNAs of men and women to have opposite signs and cancel the effect of each other in a pair. Using this property, we suggest another mechanism to cancel the effect of extra waves, which are produced by DNAs in cancer cells of a male or a female, by extra waves which are produced by DNAs in similar cells of a female or a male and prevent the progression of the disease.

The Propagation of Radio Waves in an Ionised Atmosphere

1931 ◽  
Vol 27 (4) ◽  
pp. 578-587 ◽  
Author(s):  
D. Burnett
Keyword(s):  
Wave Length ◽  
Upper Atmosphere ◽  
Radio Waves ◽  
Free Electrons ◽  
Positive Ions ◽  
Electrons And Ions ◽  
Method Of Solution ◽  
Velocity Of Propagation ◽  
The Waves ◽  
Electric Waves

Larmor has shown that if the upper atmosphere contains electrons (charge ε, mass m, density ν) and if collisions between these electrons and molecules—and also the forces between the electrons themselves—are negligible, then electric waves are propagated as if the dielectric constant of the medium were reduced by , from which it appears that, so long as the approximations are valid, the velocity of propagation of the waves can be increased indefinitely by increasing either the electron density or the wave-length λ. Several later authors have attempted to take account of the collisions between electrons and molecules, assuming free paths or velocities according to Maxwell's laws for a uniform gas, and it appears that the above law holds only for short waves; but it is doubtful how far the properties of a uniform gas can be assumed when periodic forces are acting. In the first part of this paper an alternative method of solution is given by means of Boltzmann's integral equation for a non-uniform gas, the analysis being similar to that used by Lorentz in discussing the motion of free electrons in a metal. Only the case when ν is small is considered, i.e. the interactions of electrons with one another and with positive ions are neglected. How far it is possible to increase the velocity of propagation by increasing ν is a more difficult question, but it seems possible that the forces between the electrons and ions may impose a limit just as collisions with neutral molecules limit the effect of increasing the wave-length.

scholarly journals Dampak Korona pada SUTET 500 kV Terhadap Radio Interference

2019 ◽  
Vol 11 (2) ◽  
pp. 87-97
Author(s):  
Christine Widyastuti ◽  
I Nyoman Bagus Yudha Dharma
Keyword(s):  
Breakdown Strength ◽  
Radio Interference ◽  
Radio Waves ◽  
Free Electrons ◽  
Surrounding Environment ◽  
Ieee Standard ◽  
Extra High Voltage ◽  
The Impact ◽  
Double Channel ◽  
Corona Losses

Corona can occur in SUTET because SUTET carries a high enough electric current and voltage, this causes excessive electrical pressure that is not proportional to the breakdown strength of the air around the conductor so that there will be a phenomenon where the electric field will collide with free electrons in the air and will form ionisations in the form of new ions and electrons. This process will continue as long as there are currents and voltages on the extra-high-voltage network. This certainly will affect the surrounding environment through which SUTET is included, among others, interference with radio waves (Radio Interference). The addition of the number of sub conductors is considered more effective in reducing corona losses and radio interference in each wicket than increasing the distance of the conductor to the ground. The impact of corona on a 500 kV double-channel SUTET on radio interference in the Greater Jakarta area is still within reasonable limits because it is still below the IEEE standard of 40 dB.  

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