Calculation of group indices and group heights at low frequencies
TL;DR: In this paper, a formula is derived from which the group index for normal incidence, including collision effects, can be easily computed as a function of μ and χ for frequencies below one megacycle.
About: This article is published in Journal of Atmospheric and Solar-Terrestrial Physics.The article was published on 1957-01-01. It has received 4 citations till now. The article focuses on the topics: Group (mathematics).
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TL;DR: In this article, the effect of the electron collision frequency ν on the group refractive index, for both the ordinary and extraordinary rays, under a wide variety of conditions, was shown.
11 citations
TL;DR: In this paper, a general expression for the group refractive index of the ionosphere has been deduced, considering the relevant quadrants for the phase difference between the normal and the abnormal components of the magnetic vector of the radio wave.
2 citations
TL;DR: In this paper, a general expression for the group refractive index for low-frequency radio wave propagation in the ionosphere was obtained for the case when the electron collisional frequency is small.
2 citations
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01 Jan 1948
TL;DR: In this paper, it was shown that electric waves can also heat the upper air when they travel through it and that the so-called Luxembourg effect can be traced to the influence of such a process.
Abstract: IN the Joule Memorial Lecture delivered to the Literary and Philosophical Society of Manchester on February 11, Prof. E. V. Appleton said that it was perhaps not inappropriate, in a lecture associated with a great pioneer in thermal measurements, to survey recent advances in our knowledge concerning the temperature of the upper air. Frictional work produces heat, as is well known, and Joule was the first to state the exact nature of this equivalence. An example of the heating process studied by Joule is the flight of a meteor through the atmosphere, in which case the energy of its speed is ultimately transformed into heat and light. But it has been found that electric waves can also heat the atmosphere when they travel through it. Ultra-violet light from the sun, for example, produces a belt of hot air at about the level in the ionosphere (300 km. high) where short wireless waves are reflected. It has also been found that a powerful long-wave wireless station can warm up the Kennelly-Heaviside layer to a very small but still detectable extent. The so-called ‘Luxembourg effect’ noticed by long-distance listeners, who find that they receive a long-wave programme when their receiver is tuned to the medium waves, can be traced to the influence of such a process.
350 citations
TL;DR: Theoretical analysis showed that the electron collision frequency in the ionosphere depends on the neutral particle concentration in Regions D and E and on the electron concentration in Region F as discussed by the authors.
142 citations
TL;DR: In this paper, a method for obtaining solutions to the one-dimensional wave equation which arises in the course of the application of the wave theory to the study of the ionosphere is presented.
Abstract: A method is presented for obtaining solutions to the one-dimensional wave equation which arises in the course of the application of the wave theory to the study of the ionosphere. The π's represent characteristic wave functions of the ionosphere, K0 the propagation constant of free space, ∈(x) the complex index of refraction of the ionosphere, and the primes denote differentiations with respect to the space coordinate x. The method has been applied to the following “E-layer” problem with good results.
Operating frequency —150 kc/sec Angle of incidence —NormalN (electron density) —Chapman spatial distribution with various values of maximum electron density ν (collisional frequency) —Exponentially decreasing with heightH (scale height) —10 km (constant) Earth's magnetic field —Evaluated at 100 km over State College, Pennsylvania Dispersion theory —Appleton-Hartree (Sellmeyer)
An example of the method for obtaining the wave functions and reflection coefficients is carried out in detail, and reflection coefficients are presented for five different values of maximum electron density. This method is compared with the ray optics and the W.K.B. method. The results are compared very briefly with experiment.
17 citations
TL;DR: In this paper, a tentative model for the equilibrium distribution of nitric oxide in the height range 50-100 km by considering some of the possible photochemical reactions involving ozone, nitrogen and oxygen (both molecular and atomic) and nitrous oxide.
14 citations
TL;DR: In this paper, the shape of the night-time D-layer in the coupling region and its seasonal and diurnal variations are investigated. But the results of the experimental program for the investigation of coupling phenomena at 150 kc/sec were presented.
13 citations