The electron content of the ionosphere in winter

Abstract

Observations at two closely spaced frequencies of the Faraday rotation of moon-reflected radio waves are described. These measurements have provided accurate values for the total electron content of the ionosphere for many hours on successive days. The observations reported here span a period of one month during the winter of 1960. Short-period fluctuations of the total electron content were observed. These were of about 2 to 3% in amplitude and occurred chiefly during the day-time. The gross shape of the F 2 region as determined by the ratio of the number of electrons above the F 2 peak to the number below was roughly constant during the day, but showed a wide scatter of values at night. The scale height of the ionizable constituent at the F 2 peak was found to be about the same as that of the neutral particles during the day, indicating almost complete mixing. At night, the scale height of the ionizable constituent appeared to increase with the planetary magnetic index K p . It is not possible to say if this was the result of heating of the region or the consequence of electrodynamic drifts.