Variation according to Latitude of the Electron Content of the Ionosphere near the Auroral Zone

Abstract

SOME evidence has been obtained from single-frequency Faraday measurements using the satellite 1963–49C, reported by Liszka and Taylor¹, that the sub-satellite electron content, n_t, of the ionosphere at high latitudes may consist of two components. The first component, which decreases gradually with increasing latitude, is probably produced by ultra-violet radiation from the Sun; the second, irregular, component seems to dominate at latitudes greater than 65° N. It was suggested that the latter could either be produced by low-energy corpuscular radiation, or that it could be a manifestation of transport processes. Some more accurate measurements of the electron content at high latitudes, obtained from differential Faraday observations of the multifrequency beacon satellite S–66 (1964–64A), now show that the first explanation of the irregular component seems more plausible.