The Absorption of Radio Waves in the Upper Atmosphere

1927 ◽  
Vol 29 (5) ◽  
pp. 706-716 ◽  
Author(s):  
E. O. Hulburt
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

scholarly journals The return of radio waves from the middle atmosphere—I

1937 ◽  
Vol 161 (905) ◽  
pp. 181-196 ◽  
Keyword(s):  
Physical Characteristic ◽  
Middle Atmosphere ◽  
Upper Atmosphere ◽  
Radio Waves ◽  
Sharp Distinction ◽  
Fundamental Significance ◽  
High Ionization ◽  
Collisional Damping

One of us introduced the name “Ionosphere” to designate that region of the upper atmosphere of which the most prominent physical characteristic was the occurrence of sustained high ionization densities, and which was, in consequence, of fundamental significance in the propagation of radio waves. The name, after finding its way into many languages, has been formally adopted by the Union Radio Scientifique Internationale for international use, and is now commonly applied to the region of the atmosphere above the first 90 km. It is an object of this present paper to show that this sharp distinction, although very broadly justified, is less happy than might have been hoped. It has been customary to regard the return of radio waves of measurable intensity from regions sensibly below 90-100 km. as very improbable in any save exceptional conditions, the collisional damping at lower levels being believed to ensure severe attenuation of such waves as might otherwise be returned from any temporarily densely ionized regions at moderate levels, while at still lower levels the rate of recombination seemed likely to prevent the maintenance of substantial ionization densities.

scholarly journals Radio Waves in the Upper Atmosphere

Nature ◽  
1938 ◽  
Vol 141 (3566) ◽  
pp. 407-407
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

scholarly journals Dissociation, recombination and attachment processes in the upper atmosphere—I

1937 ◽  
Vol 163 (915) ◽  
pp. 542-553 ◽  
Keyword(s):  
Reaction Rates ◽  
Upper Atmosphere ◽  
Radio Waves ◽  
Ionization Density ◽  
Pressure Discharge ◽  
Mechanical Methods ◽  
Order Of Magnitude ◽  
Quantitative Manner ◽  
The Individual ◽  
Atmospheric Ionization

The study of the properties of the earth’s upper atmosphere has now progressed so far as to provide what should be a sufficient basis for the development of a detailed theory. Since the state of the upper atmosphere approximates closely to that of the gas in a low-pressure discharge tube (except for the absence of solid boundaries), it is clear that such a theory must deal with the individual collision processes which can occur in such a system. Until the last few years no satisfactory theory of these phenomena was available, but it is now possible to apply quantum mechanical methods with reasonable expectation of results accurate at least as regards order of magnitude. We therefore propose to make use of these methods to obtain a deeper understanding of the physics of the ionosphere. In this paper we confine ourselves particularly to the qualitative study of certain problems associated with the two upper ionized layers (the E and F regions), making use of information already available concerning the probabilities of the various collision reactions which are important. The detailed evaluation of these reaction rates is being carried out, and in later papers it is hoped to deal with the various problems in a more nearly quantitative manner. The two main strata of atmospheric ionization are the E region extending roughly from 120 to 160 km. and the F region from 180 to 300 km., at night. During the day each splits into two distinct strata forming the E 1 and E 2 and the F 1 and F 2 regions. The ionization density in each region, as determined from experiments with radio waves, exhibits characteristic annual and diurnal variations besides irregular variations of considerable magnitude. The first problem which arises is the reason for the existence of the stratification. This being understood it is then necessary to account for the observed variations of density, the daytime splitting of the layers, and so on.

Refraction of short radio waves in the upper atmosphere

1926 ◽  
Vol 45 (6) ◽  
pp. 535-539 ◽  
Author(s):  
William G. Baker ◽  
Chester W. Rice
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

Refraction of short radio waves in the upper atmosphere

1926 ◽  
Vol 45 (6) ◽  
pp. 571-572
Author(s):  
Baker ◽  
Rice
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

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 The polarisation of radio waves

1928 ◽  
Vol 119 (782) ◽  
pp. 444-464 ◽  
Keyword(s):  
Great Majority ◽  
Upper Atmosphere ◽  
Mathematical Form ◽  
Actual Process ◽  
Radio Waves ◽  
Physical Conditions ◽  
Large Numbers ◽  
Electrical Layer ◽  
Physical Insight ◽  
Insight Into

The following paper is primarily an attempt to study by experimental methods the problem of the propagation of long radio waves between two points on the surface of the earth. In the early days of radio-telegraphy the propagation formulæ in general use were admittedly empirical; being derived from the simple expressions for propagation over a plane conducting surface, and modified by factors deduced from the statistical mean of large numbers of observations. While such formulae served their immediate practical purpose with considerable success, it was evident from their origin that they could give but little physical insight into the actual process of propagation. Further experiments were carried out with a view to increasing the amount of data available; but their general result was to indicate that the process was far too complex to be expressed in any reasonably simple mathematical form, and the investigation then gradually assumed the more theoretical form to which attention is being directed at present. Now it was suggested in the early days that it was extremely probable that some form of electrical layer in the upper atmosphere was responsible for many of the phenomena; and in view of the more recent work by later observers, especially Smith-Rose and Appleton, it may be taken that this view has been definitely confirmed; it is indeed now tacitly accepted by the great majority of investigators. Starting from this point, mathematical investigations have been developed, including those of Eccles, Larmor, and Nichols and Schelling most of which take into account in addition the effect of the earth's magnetic field. But in the formulae obtained in this way appear certain con­stants of the upper atmosphere to which at present no definite numerical values can be assigned, owing to our limited knowledge of the electrical and physical conditions at heights greater than 8 to 10 kilometres.

Radio Emission of Rydberg Atoms in the Upper Atmosphere Modified by High-Power HF Radio Waves

2020 ◽  
Vol 62 (10) ◽  
pp. 677-684
Author(s):  
A. V. Troitskii ◽  
V. L. Frolov ◽  
A. V. Vostokov ◽  
I. V. Rakut’
Keyword(s):  
Radio Emission ◽  
High Power ◽  
Rydberg Atoms ◽  
Upper Atmosphere ◽  
Radio Waves
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