Abstract
Abnormal features of the regular daily variation SR could be of great interest for a full understanding of the physical sources of this phenomenon, especially of the tides and electric conductivity conditions in the E layer. The subauroral part of the SR (a positive deviation from the night level, increasing polewards and occuring during a few hours at any longitude when the sun is crossing the meridian of the magnetic pole) and the polar cap SR (MAYAUD, 1965b) on the one hand, the concept of the invasion of PRICE and WILKINS (1963) on the other hand are reviewed and update. With respect to the former, one shows that they cannot be caused by the action of the azimuthal component BY of the interplanetary field, and one suggests that their source could be strong localized dynamo effects inside the polar caps, bringing about a special and single current vortex in these regions. Some equatorial counter-electrojet effects contradict the concept of the invasion and suggest the existence of vortices with reversed direction of rotation of the currents, as it would be the case for other counter-electrojet effects (MAYAUD, 1977).
