Equatorial Electrojet and electron density over Southeast Asian Region during moderate solar activity condition

Abstract

The study presents a simultaneous variation of equatorial electrojet (EEJ) current and the ionospheric F2-layer maximum electron density (NmF2) during geomagnetic quiet days and moderate solar conditions (solar radio flux, 𝐹10.7 􀵎 120 sfu). The geomagnetic measurements at Kotatobang (KTB) and Langkawi (LKW) stations have been used to estimate the magnetic daily variation in H-component and in deriving EEJ. The NmF2 data set is from Frequency Modulation Continuous Wave (FM-CW), an analogue ionosonde located at the KTB station. The study examines both the diurnal and seasonal variation in EEJ and the corresponding effect on the measured NmF2. The results obtained show that the derived EEJ at LKW shows a daytime peak which coincides with the period NmF2 measurement at KTB station depleted to a daytime low value. The role of EEJ at the LKW station correlates poorly with the NmF2 at KTB in which their correlation coefficient (r) is in the range of 0.02 to 0.04 for equinox, summer and winter, respectively. However, an r-value of 0.33 was observed when the whole data set for the year 2012 was considered. The poor correlation coefficient between derived EEJ and NmF2 measured at KTB during the moderate solar condition suggest that EEJ has little or no influence on the prevailing ionospheric condition at a low latitude station located outside the EEJ strip.