SEASONAL VARIATIONS OF S_q(Y) AND FIELD-ALIGNED CURRENTS

The seasonal variations of East component S_q(Y) observed by the geomagnetic observatory chain in the eastern part of China are analysed.It is found that some of field-aligned currents driven by ionospheric dynamo exist between south-north hemispheres in both winter and summer morning sectors.The direction of the currents is from summer hemisphere to winter hemisphere.It is possible that some reverse currents exist in the afternoon sector.