الفهرس 
Chapter 1: Basic PrinciplesOnly 14 pages are availabe for public view
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Abstract
EE-index (E Dst, EUEL), has been used to study the day to day, local time, longitudinal dependence and seasonal variation of the equatorial electrojet (EEJ). The EUEL eliminates many sources of disturbances by subtracting the median value of horizontal component (H) and the E Dst from H component data. EUEL data at a chain of stations along the dip equator have been analyzed to provide the most detailed study in this region on the equatorial electrojet. Data from eight stations have been used; these are (ANC, ILR, AAB, TIR, LKW, BCL, DAV and YAP stations) for a period of three years 2009, 2010 and 2011. As expected there is a local time dependence of EEJ, EEJ-related magnetic effects in the daily variations of the horizontal component has been found to appear at about 6 LT, reach to the maximum near local noon and vanish after 18 LT. Simultaneous surface magnetic records from eight stations in different longitude sectors have been used to study the longitudinal dependence, three years have been analyzed separately, a very good agreement between the results have been found, this study has shown that the magnetic signature of the EEJ is stronger in South America with a maximum at about 77◦W, it is followed by a minimum in West Africa at about 4 ◦E. The EEJ magnetic signature is weak in Asia - except Philippine - , with a minimum in India, between 70◦ and 90◦E. A secondary maximum is at about 125 ◦E. The seasonal variations of the equatorial electrojet have been studied by both the whole data set (disturbed and quiet days) and quiet days’ data. It has been proved that there is a semiannual variation in the equatorial electrojet with equinoctial maxima.