MINOR ATMOSPHERIC CONSTITUENTS AND ION COMPOSITION OF E-REGION

An analysis is described of rocket-measured profiles of electron density and relative ion abundances in the E-region between heights of 110 and 150 km. The profiles for three conditions are considered, viz. equilibrium daytime and nighttime conditions, and for a period over sunrise. Using published values of solar flux, cross sections and reaction rates, it is shown that the observed daytime and nighttime O2 + and NO+ abundances cannot be explained unless a reaction of the form O2 + + X → NO+ + Y, where X is a minor neutral constituent, plays a dominant role. This reaction is important also during sunrise. The results suggest a pronounced solar control on the concentration of X and a relatively high abundance of O2 + (about 60 per cent) in the height range 110-130 km during sunrise. The range of values for the concentration of X deduced in this work encompasses the published measured values of the concentration of NO in this region. This suggests that NO is the minor neutral constituent involved, although the possibility that N is also important cannot be ruled out. © 1969.