Accession Number : AD0638908

Title :   VLF RAY TRACING IN A MODEL IONOSPHERE.

Descriptive Note : Doctoral thesis.

Corporate Author : IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Shawhan,Stanley D.

Report Date : AUG 1966

Pagination or Media Count : 187

Abstract : 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)

Descriptors :   (*IONOSPHERIC PROPAGATION, VERY LOW FREQUENCY), WHISTLERS, MODEL THEORY, GRAPHICS

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE