Solar and Magnetic Declination Control of the Pre-Reversal Enhancement in the Equatorial E- and F-Region Electric Fields

The horizontal drift velocity of electrons in the E- region, and their vertical drift velocity in the F- region show regular enhancements prior to their morning and evening reversals, in the equatorial ionosphere. These enhancements are more pronounced in the evening than in the morning and also show significant seasonal variations. The influence of solar and magnetic declination angles on the electrical coupling of non-equatorial E and F- regions being responsible, at least partly, for these observations, is discussed here. Possible future observations, that can conclusively establish this hypothesis are also suggested.