Brief study of equatorial electrojet and global Sq currents at Southeast Asia region

The equatorial electrojet (EEJ) is a strong eastward current flowing in a narrow band along the magnetic dip equator. This current interacts with the global Sq current and caused abnormally large amplitude of geomagnetic filed component measured at the magnetic dip equator station. In this study, we use a new EE-index (EDst and EUEL) derived from MAGDAS/CPMN stations to get continuous data of local EEJ magnetic component and global Sq magnetic component. In order to isolate EEJ component, we subtract the possible contributions of global Sq to the magnetometer measurements using a two-station method. The magnetic signature of EEJ strength is calculated as a difference between the EUEL index of dip equator station and the EUEL index of station few degrees away from dip equator. The global Sq current component at dip equator station is then given by the subtraction of EEJ component from EUEL index of dip equator station. Analysis is performed using data from two pairs of stations at Southeast Asia region for a year of 2011. We then examined seasonal variations of the both currents component together with longitudinal dependence of EEJ component in Southeast Asia region.