Evidence is presented to show that during epochs of high sunspot activity, the duration of manifestation of equatorial spread-F (ESF) irregularities in the Earth's equatorial ionosphere undergoes a systematic modulation around the times of crossing of the heliospheric current sheet by the Earth. The modulation which is assessed as an indirect and ‘geomagnetic activity-associated effect’, is characterised by an enhancement in the duration of ESF conditions prior to the current sheet crossing and a reduction thereafter. It is suggested that the observed response of the equatorial ionosphere to the current sheet passage is primarily a manifestation of the geomagnetic activity related modifications in the equatorial east-west electric field in the post-sunset period.
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Sastri, J. H(National Research Council of Canada, 1985-04)
A superposed epoch analysis has been carried out of h′F values at Kodaikanal (10°14′N, 77°28′E, dip 3.0°N) pertaining to years of high sunspot activity using solar wind sector boundary passages past the earth as key days. ...
Rastogi, R. G(Indian Academy of Sciences, 1975-02)
Experimental data on daily variations in the geomagnetic field are analyzed for evidence of counterflowing electrojets. In particular, the disappearance of the q type of Es layer (Es-q) and the appearance of blanketing-type ...
