Thermal structure of the temperate latitude ionosphere

Abstract

The paper reviews previous theoretical attempts to explain the altitude variation of electron and ion temperature in the ionosphere at temperate latitudes. New model calculations are then presented, which include all known important physical processes with the possible exception of ion conduction. The relative importance of the solar u.v. heat input and heat conducted from the protonosphere in controlling the electron temperature profile is investigated by varying these two parameters. Attempts are then made to match published electron temperature profiles obtained at Millstone Hill (Massachusetts, U.S.A.) in 1964 and St. Santin (France) in 1966. In this work the observed electron density profile is employed in the calculations and appropriate neutral densities and temperatures were taken from the Harris and Priester (1962) atmosphere models. Fairly good agreement can be obtained for the Millstone results when the solar u.v. heat input is reduced to about one third the value estimated by Dalgarno et al. (1963) , and when the protonospheric heat flux is raised to ∼5 × 10 9 eV/cm 2/sec, i.e., an order of magnitude higher than some earlier estimates ( Geisler and Bowhill, 1965 b) .