Accession Number : AD0481992

Title :   ATTENUATION OF HYDROMAGNETIC EMISSIONS IN THE IONOSPHERIC WAVEGUIDE.

Descriptive Note : Semiannual rept. 1 Sep 65-28 Feb 66,

Corporate Author : LOCKHEED MISSILES AND SPACE CO INC PALO ALTO CA PALO ALTO RESEARCH LAB

Personal Author(s) : Wentworth, R. C. ; Tepley, Lee

Report Date : 25 MAR 1966

Pagination or Media Count : 45

Abstract : It has been suggested that hydromagnetic (hm) emissions propagate toward the equator from high latitudes in an ionospheric waveguide centered at the Alfven velocity minimum in the F region. In the present paper the effects of absorption in and around the waveguide are considered. In order to simplify the mathematical treatment the ionospheric Alfven velocity profile is approximated by a squarewell profile. A conventional mode theory analysis - valid for all wavelengths - is then carried out. It is found that at hm-emission frequencies (around 1 cps) and for distances of several thousand miles, there is moderate nighttime waveguide attenuation at sunspot maximum and negligible attenuation at sun-spot minimum. Also the calculated value of group velocity for nighttime sun-spot minimum is in close agreement with experimental observation. (Author)

Descriptors :   (*MAGNETOHYDRODYNAMICS, IONOSPHERIC PROPAGATION), ATTENUATION, IONOSPHERIC DISTURBANCES, VELOCITY, SUNSPOTS, PARTIAL DIFFERENTIAL EQUATIONS, REFLECTION, GEOMAGNETISM, MAGNETIC FIELDS, BOUNDARY VALUE PROBLEMS, ELECTRIC FIELDS, WAVEGUIDES, WAVE PROPAGATION, IONOSPHERE.

Subject Categories : Atmospheric Physics
      Plasma Physics and Magnetohydrodynamics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE