Studies of the structure and dynamics of the D region of the polar ionosphere during solar flares in April 2004

Abstract

[1]  The results of observations of the polar lower ionosphere by the partial reflection method during moderate solar flares in April 2004 are presented. The structure of the electron concentration profile in the ionospheric D region and the effects of the impact on it of X-ray radiation of the flares both in quiet and disturbed conditions are considered. It is shown that at altitudes below 75 km the electron concentration is proportional to the intensity of X-ray radiation from a solar flare. This manifests the existence of a linear recombination law at these heights.

Received 22 March 2005; revised 20 September 2005; accepted 11 October 2005; published 20 January 2006.

Keywords: Lower ionosphere; Solar flares; Electron concentration.

Index Terms: 2479 Ionosphere: Solar radiation and cosmic ray effects; 2435 Ionosphere: Ionospheric disturbances; 2419 Ionosphere: Ion chemistry and composition.