ИСТИНА

We compare the simultaneous magnetometer, SuperDARN radar, and GPS observations during Pc5 wave event on March 02, 2002. A possible correspondence between those instruments may help to determine the mechanism of the ionosphere modulation by magnetospheric disturbances. Transient Pc5 pulsations (2.6 mHz) in the morning sector, stimulated by the solar wind density jumps, have been detected simultaneously by ground magnetometers and the Kodiak and King Salmon SuperDARN radars. Besides that, pulsations with the same periodicity have been found in the rate of total electron content (TEC), dTEC/dt (ROT), variations in several GPS radio paths. The ratio between the spectral amplitudes of the Doppler velocities and magnetic pulsations (X component) on the ground are Vx/Bx~7-12 (m/s)/nT and Vy/Bx~27 (m/s)/nT. The ratio between the oscillation amplitudes of ROT and ionospheric Doppler meridional (Vx) and azimuthal (Vy) velocities are ROT/Vx~0.02-0.07 (dTECu/min)/(m/s) and ROT/Vy~0.004 (dTECu/min)/(m/s). The correspondence between simultaneous periodic variations of the ionospheric Doppler velocity and geomagnetic field can be reasonably well interpreted quantitively on the basis of theory of Alfven wave interaction with the thin ionospheric layer. However, order-of-magnitudes estimates of possible TEC modulation mechanisms show that a responsible mechanism which can interpret the observed ratios has not been found yet.