Variation with time of the asymmetry index between NH and SH, and of the signed magnetic flux from the two hemispheres. Panel a: normalized asymmetry flux index for NH and SH, θ = [0° , ± 70° ] derived from the solution of the NLFFF extrapolation at r = 1.0 R_s (dash-dotted black line), 1.5 R_s (dashed blue line), and 1.8 R_s (solid red line). Panel b: signed flux for the NH at r = 1 R_s (thick solid red line), r = 1.5 R_s (dashed red line), and r = 2.2 R_s (dash-dotted red line) and for the SH at r = 1 R_s (thin solid blue line), r = 1.5 R_s (triple dot-dashed blue line), and r = 2.2 R_s (dotted blue line).