Diffusion of ions in the ionosphere

Abstract

(1) Introduction —The variation of ionic density in the ionosphere with height at any time of the day has been the subject of a number of theoretical studies by E. O. Hulburt and S. Chapman, amongst others. Chapman's discussion is based on the supposition that the disappearance of electrons in the ionosphere is due entirely to electron‐positive ion recombinations, and Appleton and Naismith [see 1 of “References” at end of paper] find that this simple theory agrees well with the observed variation of the maximum electron‐density in the E ‐ and F 1 ‐layers. His theory, however, does not take into account the possible influence of the downward diffusion of ions and an approximately equal number of electrons. Hulburt [2], summing up the results of his investigation, remarks that as regards the variation of ionic density “there is an uncertainty in the case of F 2 and F 1 which may or may not turn out to be important.