Solar cosmic rays and changes in the polar middle atmosphere and ionosphere

Abstract

This paper is a first-stage study of the effect the solar cosmic rays cause in the polar lower ionosphere though some aspects of the effect on polar atmosphere have been already studied by other authors. Numerical simulations have been made to find the response of both neutral and ionised species in the middle atmosphere to the strong solar proton events (SPE) with the onset on October 19, 1989. Both temporal and spatial (vertical) deviations of neutral species induced by the SPE have been calculated by a 1-D time-dependent photochemical model separately for daytime and nighttime. Changes of the neutral composition due to this event have been analysed by Krivolutsky et al. (Advances in Space Research 27 (2001) 1975). Here, the neutral species deviations are used in a 1-D model of the lower ionosphere to calculate the response of ionised components and other parameters of the lower ionosphere. The three orders of magnitude enhancements of electron and ion concentrations are obtained for several days after the SPE. The ionospheric parameters are changed for about 2 weeks. Relative abundance of the most typical negative ions is found changed for the first 2 days. Results of model calculations are in reasonable agreement with available (rare) observations.