D-region electron densities and collision frequencies from Faraday rotation and differential absorption measurements

Abstract

A rocket technique for measuring electron density and collision frequency in the lower ionosphere is described. Absolute values of electron density were determined by a radio propagation experiment, and detailed height variations were measured with a Langmuir probe. In the derivation of the collision frequency profiles, a pressure profile was employed which was found from measurements of the absorption of solar Lyman-α radiation, made on the same flight. The analysis of results from one such flight is described in some detail. The payload was launched from South Uist, Scotland on 19 June 1969 at a solar zenith angle of 44° using a Petrel rocket. Electron density and collision frequency profiles are presented.