The Equatorial Ionization Anomaly (EIA) refers to a prominent irregularity in the distribution of ionization density within the ionosphere, situated near the magnetic equator, with two distinct crests at around ±150 in magnetic latitude- where ionization densities are significantly higher – and a trough at the magnetic equator in the F2 layer. This irregularity in ionization density has garnered considerable attention from researchers and scientists due to its complex underlying mechanisms and its significance on both the space and ground based communication facilities. This paper aims to explore the mechanisms and characteristics of the EIA, its impacts on communication and navigation systems, and various models that contribute to our current understanding of this enigmatic phenomenon. It also delves into spatio-temporal variability of the EIA, and finally proffers clarification on some misconception on the subject matter of the equatorial ionization anomaly.
Keywords: The Equatorial Ionization Anomaly; Ionosphere; Equator
