Effects of solar activity on ionospheric current system in the Southeast Asia region

Abstract

The equatorial ionospheric current system is composed of equatorial electrojet (EEJ) and solar quiet (Sq) that flow in the eastward direction. That being mentioned, this study looked into the changes in ionospheric currents stemming from geomagnetic storm disturbances at different levels of solar activity during solar cycle 24. This analysis was performed by employing an EEJ index known as EUEL, which is calculated from northward geomagnetic component data measured using ground-based magnetometer at five different latitudes across the Southeast Asia region. Based on the outcomes, the impacts of geomagnetic storm on EEJ currents were observed at 1200 LT and 1100 LT, respectively, during high and low solar activity levels. Time delay was associated with changes in EEJ peak time at varied activity levels. This case study reveals that EEJ value at peak time of high solar activity decreased significantly during the main phase of geomagnetic storm.