Ionospheric manifestations of geomagnetic pulsations at high latitudes

In this paper the interrelation between geomagnetic pulsations and variations in frequency Doppler shift (Fd) of the ionosphere-reflected radio signal is under investigation. The experiment on simultaneous recording of Fd variations and geomagnetic pulsations was organised at high latitude station in Norilsk (geomagnetic latitude and longitude 64.2 N, 160.4 E, L=5.3) during Febrary-April of 1995-98. Thirty cases of simultaneous recording of duration from 10 min to two hour were analysed: 6 cases of simultaneous recording of variations Fd and regular geomagnetic pulsations Pc5; and 25 cases of recording of Fd variations and irregular pulsations Pi2. On the basis of experimental results, the following conclusions have been drawn: a) Hydromagnetic waves in the range of regular Pc5 pulsations, when interacting with the ionospheric F2 layer, make the main contribution to short-period Fd variations. The possible mechanism of Fd variations are oscillations of electron density, associated with distribution of a hydromagnetic wave in an ionosphere. b) 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.