Ion and electron temperatures in the topside ionosphere

Experimental and theoretical ion and electron temperatures in the topside ionosphere are investigated. Experimental results come from an analysis of incoherent-scatter data taken at Arecibo, Puerto Rico. Consideration of the energy balance equations gives the theoretical ion and electron temperatures. Two ions, O+ and H+, are assumed to be the only ions present in the topside ionosphere. Experimental evidence shows that a third ion, He+ is relatively unimportant compared to O+ and H+. Photoionization of neutral particles, charge transfer, and diffusion of these charged particles are the important physical processes used to calculate number density profiles. O+ and H+ number densities are shown to affect the O+, H+, and electron temperatures. Analysis of theoretical autocorrelation functions of the incoherent-scatter power spectra shows that number densities and temperatures of O+, H+, and electrons can be deduced from experimental autocorrelation functions. Experimental temperature results indicate that the maximum difference between H+ and O+ temperatures occurs at 550 km. This agrees with temperatures calculated from the energy balance equations. The experimental and theoretical H+ and O+ temperatures agree fairly closely from 200 to 1200 km, while the electron temperatures agree from 400 to 1200 km