Prediction of Faraday Rotation Angles at VHF and UHF

摘要

A study of the Faraday effect has been made and some procedures have been outlined for estimating the amount of Faraday rotation imposed upon linearly polarized radar waves in the ionosphere. The study involves the construction of suitable models for the ionosphere and the geomagnetic field. In the estimation analysis, variable scale height Chapman profiles are used to represent the average ionosphere. The magnetic field model is embodied in a rather standard tabular procedure, which makes use of Navy Oceanographic Office charts. The steps were determined which are required to predict an expectation value for the amount of Faraday rotation imposed upon the radar signals reflected from ionospheric and superionospheric targets. These steps involve (a) obtaining a magnetic field parameter from the tabular procedure and (b) estimating the electron content below the target. Both steps (a) and (b) require the knowledge of maximum usable frequencies from Bureau of Standards CRPL maps. (Author)