In the low-latitude F-region meridional winds have a dominant component parallel to the magnetic ,eld and thus do not drive a current. Remember that in the F-region the Hall conductivity is negligible. Zonal winds, which are predominantly perpendicular to the magnetic ,eld, thus drive a current perpendicular to the wind and the magnetic ,eld. Near the equator this current is almost vertical. Fig. 10 illustrates the wind driven current in the F-region and the E-region closure current that will result from any divergence in the F-region current. Dashed lines illustrate ,eld-aligned currents that complete the current loop. Note that since only the Pedersen conductivity is important, the F-region dynamo drives a current that is predominantly in the magnetic meridian. A simple application of Eq. (9) assuming that the horizontal
current is divergent at the edges of the regions and considering only the electric polarization ,eld in the magnetic meridian shows that