Author : Richard Michael Jones
Publisher :
Page : 204 pages
File Size : 24,93 MB
Release : 1975
Category : Government publications
ISBN :
Author : Ming S. Wong
Publisher :
Page : 18 pages
File Size : 41,48 MB
Release : 1971
Category : Ionosphere
ISBN :
Ray patterns are presented which delineate the propagation of radio signals to large distances by ducting under super-refracting conditions in the troposphere, ionosphere, and magnetosphere. The unity of ducting is emphasized in the sense that the ducts, whether they occur in the troposphere, ionosphere, or magnetosphere, all have formally similar features. This unity follows from the circumstance that the rays which propagate to large distances are those which graze a super-refracting layer at shallow glancing angles and which generally traverse only those regions of the propagation medium where the refractive index deviates but slightly from the free-space value. (Author).
Author :
Publisher :
Page : 49 pages
File Size : 30,71 MB
Release : 1967
Category :
ISBN :
The problems of tracing rays in the ionosphere for radio propagation, primarily for high frequencies (3 to 30 Mc/s) and above, are discussed. The limitations on 'classical' geometrical optics are described, and their applications to ionospheric problems are indicated. Some 'simplified' processes of ray tracing, which apply well at the earth's surface, but not in the ionosphere itself, are first presented. Next, ray-tracing methods which apply in an isotropic ionosphere, when the effects of the earth's magnetic field are negligible, are discussed. The results are then extended to more general cases of an isotropic medium, and then to an anisotropic medium (such as the ionosphere in the presence of the earth's magnetic field). Certain special problems which must be considered in ray-tracing studies are described next and finally, a few of the important areas for the application of ray tracing are noted.
Author : Stanley Dean Shawhan
Publisher :
Page : 358 pages
File Size : 48,84 MB
Release : 1966
Category : Whistlers (Radio meteorology)
ISBN :
A VLF ray tracing study in a model ionosphere including ions is presented. A review of previous VLF ray tracing methods is given. The physical meaning of rays and ray paths is discussed and it is concluded that for ray tracing in the ionosphere the wave packet and Poynting vector approaches give the same results. Two-dimensional ray tracing equations are derived for the case of a horizontally stratified ionosphere and the derivation of three dimensional equations are integrated for the special cases of exactly transverse and exactly longitudinal propagation but it is concluded that neither case can persist for very-low-frequency radio waves in the ionosphere. Also the condition for reversibility of a ray path are derived. It is found that the computer program for numerical integration of the ray tracing equations can retrace a path to 0.3% in latitude and 0.02% in wave normal angle and can reproduce known results for the horizontally stratified model. (Author).
Author : M. S. Wong
Publisher :
Page : 56 pages
File Size : 14,5 MB
Release : 1973
Category : Computer programs
ISBN :
An accurate geomagnetic-field model, consisting of the dipole plus seven higher-order harmonics in dipolar coordinates, is incorporated into a computer program for three-dimensional ray tracing. Three options of using magnetic-field models are provided: (1) using accurate field in computing both the ray trajectory and the propagation-aspect angle between the geomagnetic-field vector and the wave-normal vector associated with each point along the ray; (2) using the dipole field for computing rays but using the accurate field for computing aspect angles; (3) using the dipole field for both the rays and aspect angles. Comparisons are made among the results computed, using the three options, in the HF band for a nighttime polar ionosphere and for a noontime equatorial ionosphere. Typical differences of few to ten degrees occur in the aspect angle, for aspect angles near 90 degrees -- the value under which geomagnetic-field-aligned ionization, if present, would give rise to maximum backscatter of HF waves and thus cause clutter in Over-the-Horizon radars. (Author).
Author : Ming S. Wong
Publisher :
Page : 28 pages
File Size : 30,47 MB
Release : 1975
Category : Backscattering
ISBN :
Swept-frequency traces of minimum group-path length in backscatter-radar ionograms, computed for a measured three-dimensional electron distribution in the midnight sector of the polar ionosphere, are presented. Also presented are minimum group-path traces computed for trial electron distributions chosen to simulate the group-path traces of the measured electron distribution, and to show the effects on the group-path traces as consequences of variations made upon major features of the trial electron distributions.
Author : Ming S. Wong
Publisher :
Page : 0 pages
File Size : 50,46 MB
Release : 1971
Category : Ionosphere
ISBN :
Ray patterns are presented which delineate the propagation of radio signals to large distances by ducting under super-refracting conditions in the troposphere, ionosphere, and magnetosphere. The unity of ducting is emphasized in the sense that the ducts, whether they occur in the troposphere, ionosphere, or magnetosphere, all have formally similar features. This unity follows from the circumstance that the rays which propagate to large distances are those which graze a super-refracting layer at shallow glancing angles and which generally traverse only those regions of the propagation medium where the refractive index deviates but slightly from the free-space value. (Author)
Author : J. Haselgrove
Publisher :
Page : 150 pages
File Size : 10,56 MB
Release : 1958
Category :
ISBN :
Author : Sheridan Lambert
Publisher :
Page : 212 pages
File Size : 17,88 MB
Release : 1978
Category : Ionosphere
ISBN :
Author : VICTOR HUGO. GONZALEZ
Publisher :
Page : 84 pages
File Size : 35,7 MB
Release : 1961
Category : Ionosphere
ISBN :
