Fig. 12

The top four maps show the primary ionospheric E-region current function \(\Psi\) at \(110\,\hbox {km}\) altitude during vernal equinox centered on noon local time for 06, 12, 18, and \(00\,\hbox {UT}\). The bottom four maps show \(\Psi\) centered at local noon and \(12\,\hbox {UT}\) on the 21st day of March, June, September, and December. Solid/dashed contour lines indicate counter-clockwise/clockwise current flow. A \(10\,\hbox {kA}\) current flows between contours. Red curves represent QD latitudes of \(\pm\, 55^\circ\) and blue represents \(0^\circ\). A value of \(F_{10.7}=100.0\times 10^{-22}\,\mathrm{W}/\mathrm{m}^2/\mathrm{Hz}\) was used for evaluation