Rapid, intense Faraday polarization fluctuations of satellite HF and VHF beacon signals have been shown to be caused by wave scattering from density irregularities. Except in the case of HF signals (e.g., 20 MHz), irregularities with Gaussian spectra cannot affect the polarization of satellite signals as effectively as irregularities with power law spectra. It is adequate to use the theory of single scattering for describing the Faraday polarization fluctuations even in cases involving large density fluctuations, such as those of 41-MHz signals near the magnetic equator and those of 136-MHz signals near the equitorial anomaly region. |