Accession Number : AD0715338

Title :   The Possibility of Electromagnetic Wave Ducting in the Ionosphere,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Stephanakis,S. J. ; Balwanz,W. W. ; Ament,W. S. ; Faust,W. R.

Report Date : 06 NOV 1970

Pagination or Media Count : 25

Abstract : The refractive index of the ionosphere varies with altitude, providing optimum wave curvature for around-the-world propagation. The variation also provides ducts which tend to focus waves into this optimum curvature. Simple calculations using published ionospheric properties are used to demonstrate the wave curvature and the duct structure. The duct altitude varies between 90 and 300 km depending on the frequencies used and the diurnal variations of the ionosphere. Signal loss varies widely, providing around-the-world propagation with less than a 5-dB loss per earth traverse in some of the duct configurations. Methods of coupling into the ducts are assumed based on reports by other investigators. Signal scatter, which provides one method for coupling into and out of the duct, adds to the calculated signal loss from electron collisons. (Author)

Descriptors :   (*ELECTROMAGNETIC RADIATION, IONOSPHERIC PROPAGATION), (*IONOSPHERE, ELECTRON DENSITY), ELECTRIC FIELDS, DIURNAL VARIATIONS, GEOMAGNETISM, ATMOSPHERIC REFRACTION

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE