Ionospheric Faraday Modulation of the Intensity of Radio Astronomical Signals

摘要

The ionospheric effect during transionospheric propagation is inversely proportional to the square of frequency f[I]. Therefore, it is still believed that VHF ionospheric distortions of radio astronomical signals are negligible and they can be ignored in the interpretation of observations. However, the author of the present paper had suggested as early as 1981 that the above opinion is far from accurate [2]. Let us use the prolonged solar radio emission on January 17, 2005, to examine distortions of the radio emission profile caused by the Faraday amplitude modulation, a simple model of which is presented in [2].