Latitudinal variation of ionospheric currents in Southeast Asian sector

The equatorial electrojet (EEJ) is a current system caused by the enhanced ionospheric conductivity near the dayside magnetic dip equator. In this study, we attempt to obtain the latitudinal profile of Sq and total current component (EEJ+Sq) and consequently attain the EEJ latitudinal variation. Analysis is carried on using magnetic data recorded at six stations in Southeast Asian sector. The data used are equatorial electrojet index, EUEL, which were calculated from geomagnetic northward, H, component on geomagnetically quiet days. We further compared latitudinal profile of Sq and total current during solar minimum (2008) and solar maximum (2014) in order to study their solar cycle dependence. Furthermore, we examined the EEJ circuit for both solar activity period. Result shows that as the EEJ strength increase with solar activity, it contribute to higher increase in total current during 2014, and consequently contribute to significant difference in the total current latitudinal profile during 2008 and 2014. On the other hand, the EEJ latitudinal variation illustrates the current circuit where the reverse current was observed to start on the flanks of dip equator at about 5° and terminate at less than 10° latitude in both hemispheres.