Ionospheric manifestations of geomagnetic pulsations at high latitudes

In this paper the interrelation between geomagnetic pulsations and variations in frequency Doppler shift f d of the ionosphere-reflected radio signal is under investigation. The experiment on simultaneous recording of f d variations and geomagnetic pulsations was organized at high latitude station in Norilsk (geomagnetic latitude and longitude 64.2 degree(s) N, 160.4 degree(s) E, L equals 5.3) during February - April of 1995 - 98. Thirty cases of simultaneous recording of duration from 10 min to two hour were analyzed: 6 cases of simultaneous recording of variations fd and regular geomagnetic pulsations Pc5; and 25 cases of recording of f d variations and irregular pulsations Pi2. On the basis of experimental results, the following conclusions have been drawn: (1) Hydromagnetic waves in the range of regular Pc5 pulsations, when interacting with the ionospheric F2 layer, make the main contribution to short- period f d variations. The possible mechanism of fd variations are oscillations of electron density, associated with distribution of a hydromagnetic wave in an ionosphere. (2) There exists an unquestionable interrelation between fd variations of the sporadic E layer-reflected radio signal and irregular Pi2 pulsations, but for some reasons it is traced poorly.