Total electron content and magnetic field intensity over Ilorin, Nigeria

Simultaneous 10 quiet days records of slant total electron content (STEC) and the horizontal magnetic field intensity (H-field) from each month of the year 2009 are employed for this work. The STEC and the H-field are measured from Global Positioning System (GPS) and the Magnetic Data Acquisition System (MAGDAS), respectively at Ilorin, Nigeria. The vertical total electron content (VTEC) and solar quiet of H-component (SqH) values are estimated from the STEC and H-field data respectively. Daily maximum value of SqH (DSqH) in October is 87 nT and the minimum value in January is 18 nT around 1000–1200 LT. With the exclusions of months with pre-noon peaks, maximum daily value of VTEC (DTEC) was observed at 1500 LT in October with a value of 34 TECU and with a minimum value of 24 TECU in February. During the pre-sunrise towards the sunrise period at the equatorial-trough, prominent westward electric field associated with increasing DSqH variations were due to probable late reversal of the westward nighttime to eastward daytime electric field, which plays significant role of generating equatorial ionization anomaly (EIA) at the equatorial-trough. The maximum peak time of DSqH closely determines the time of pre-noon peak on the DTEC variability when there is no prominent CEJ during the rising flank. On the decaying flanks, CEJ were observed to impede plasma deposition on DTEC variation. The estimates of correlation coefficient (cc) of DTEC and DSqH are also investigated. Seasonal variations investigated show that there exist a relationship between DTEC and DSqH, which is an evidence of EIA.

► The equatorial ionization anomaly is characterized by plasma transportation.
► The vertical plasma drift was initiated by the equatorial electrojet.
► The equatorial electojet is peculiar to solar quiet.