Ion Kinetics in the Lower Ionosphere

ABSTRACT

A comprehensive re-examination is made of the ion kinetics of the lower ionosphere in the light of recent space measurements of solar XUV radiation, ion composition and electron density profiles, and laboratory measurements of rate constants. The ionic chemistries of the ions NO⁺, O⁺₂, N⁺₂ and O⁺ are discussed. An approach in terms of the individual ionic chemistries and the recognition of NO⁺ abundance below 80 km., introduce some fundamental changes in the equations governing lower ionospheric ionization. Laboratory coefficients are found to be generally consistent with the data excepting for the process N⁺₂ + O₂ → O⁺₂ + N₂. For the process O⁺₂ + N₂ → NO⁺ + NO, for which laboratory observations give only an upper limit, a value of 1 × 10⁻¹⁸ cm.³/s. is inferred. A value of 3×10⁻⁸ cm.³/s. is obtained for the dissociative recombination coefficient of NO⁺.