Fig. 7
From: Sunlight effects on the 3D polar current system determined from low Earth orbit measurements
Estimates of total horizontal ionospheric currents. Total horizontal ionospheric currents, the sum of the divergence-free (equivalent) current and curl-free current. Northern hemisphere currents are shown on top and Southern hemisphere currents at the bottom. The left column corresponds to Fig. 3, and the right corresponds to Fig. 4. The sunlight terminator locations are indicated with red bars and arrows pointing at the allowed locations where the terminator may cross the noon–midnight meridian