Abstract:
From a comparative study of the diurnal variation of equatorial geomagnetic field during abnormal quiet days (AQDs) and normal quiet days (NQDs). It is shown that an additional field exists in the equatorial region during AQDs superposed on a normal quiet days S/sub q and electrojet field. The H-component of the additional field exhibits a prominent southward maximum around 1100 hrs. LT and a secondary northward maximum around 0800 hrs LT on AM AQDs and around 1400 hrs LT on PM AQDs. The associated effects in the Z-component at a station about 2.5 degree N of the dip equator support these features of the additional field on AQDs.
