Irregularities in the Ionospheric Electron Density Distribution Causing Radio Wave Scintillation

Abstract

Shortly after the discovery of discrete sources of cosmic radio noise it was found that the strength of the sources was variable. First, it was believed that the sources varied, but Smith, Little and Maxwell found that there was no correlation between the fluctuations recorded at two points on the ground separated by a distance of the order at 100 km. From this observation it could be concluded that the fluctuations originate in the medium through which the radio waves propagate. The effect is similar to the scintillation of stars in the visible frequencies. Scintillations have been observed at radio wavelengths varying between 20 m and 8 mm in the radiation coming from the sun, Cygnus, Cassiopeia, Taurus, Virgo and Centaurus and also in transmissions from artifical satellites.