Phase Variability of <i>S_q</i>(<i>H</i>)&amp; the Ionospheric Equatorial Anomaly

Abstract

A study is made of the behaviour of the equatorial ionization anomaly in the Indian region on days with an abnormal <i> S_q</i>(<i>H</i>) phase limited to the electrojet belt. The anomaly is found to disappear or reduce in strength quite consistently within about 2 hr of the onset of complete or partial counter-electrojet conditions, responsible for the shift of the <i>S_q</i>(<i>H</i>) phase from the normal time interval. Further, the remarkably poor development of the anomaly in the afternoon period in the Indian region as compared to that in the East Asian region has been shown to occur only on days with an abnormal <i>S_q</i>(<i>H</i>) phase in the Indian equatorial region. These results lend further support to the view that the occurrence of an abnormal <i>S_q</i>(<i>H</i>) phase at electrojet locations is closely associated with perturbations in the electrojet electric field.