Abnormal quiet days and the effect of geomagnetic activity on the diurnal variation of equatorial geomagnetic field

Abstract

It is shown that a conspicuous noontime positive deviation 10 the asymmetric component or the H field at equatorial electrojet stations, associated with the solar wind on quiet days with A/subp~5, does not manifest if abnormal quiet days' (AQDs) and hence the influence 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 H field on quiet days With A/subp~5 at electrojet stations is primarily due to changes in the local ionospheric dynamo region rather than in the solar wind.