STUDY AND INVESTIGATION OF THE PROPAGATION OF WHISTLER MODES THROUGH THE IONOSPHERE.
DEFENSE RESEARCH CORP SANTA BARBARA CALIF
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Specific information was sought concerning the attenuation and dispersion of whistlers because of collisional absorption, or because of reflection losses arising from gradients in refractive index or from discontinuities in the magneto-ionic duct. The concept that collisional absorption occurs almost entirely within the D region was maintained. Reflection losses due to steep gradients in the refractive index are small, equal to, or lower than 0.1 db reflection losses at the boundary between the ionosphere and the atmosphere, however, may produce attenuations of 15 db. Discontinuities in the magneto-ionic duct, due to regions of low electron density or to regions of turbulence, appear to have little influence on the intensity of whistler signals. This conclusion is based both on the estimated magnitude of the discontinuities likely to be encountered in the outer atmosphere as well as the machine calculation of whistler modes. Subsidiary investigations were carried the density distribution and collision frequencies of electrons in the ionosphere the formal structure of magneto-ionic theory and two investigations of models of magneto-ionic ducts.