Abnormal Quiet Days & the Effect of Geomagnetic Activity on the Diurnal Variation of Equatorial Geomagnetic Field

Abstract

It is shown that a conspicuous noontime positive deviation in the asymmetric component or the H field at equatorial electrojet stations, associated with the solar wind on quiet days with <i>A</i>_p ~ 5, does not manifest if abnormal quiet days'(AQDs) and hence the influence of counter-electrojet conditions associated with them are taken into consideration. It is pointed out that the noontime positive swing or the asymmetric component in the <i>H</i> field on quiet days with <i>A</i>_p ~ 5 at electrojet stations is primarily due to changes in the local ionospheric dynamo region rather than in the solar wind.