| Popis: |
IGY data from eight South American stations covering a latitudinal range of approximately 35° have been used in a new study of the equatorial electrojet. It was found that the space gradients of Sq(H) were appreciable at latitudes just beyond those normally regarded as constituting the electrojet zone. This suggests that any simple procedure for separating the total magnetic field into normal and electrojet components will be unreliable. There is considerable disagreement between the observed results and those expected on the basis of the uniform band model of the electrojet, especially with respect to the vertical component. It is suggested that this discrepancy may be due to the complex form of the Sq vortices, the N vortex penetrating well into the S hemisphere in the morning hours of the June solstice and the S vortex penetrating above the magnetic equator in the early morning hours of the December solstice. Both vortices tend to be drawn into the region of enhanced conductivity at the magnetic equator during the Equinoxes, but at other times of the year, one vortex appears to provide the predominant contribution to the currents in the magnetic equatorial belt. The importance of observing all three magnetic components simultaneously at a wide range of stations in the equatorial region is stressed. |
