Upper panel: A_uni versus time (Julian days minus t₀ = 2   450   000) for all PIL pixels (solid line), pixels superimposed on filaments (dashed line), pixels at distances of smaller than 30 Mm from a filament (dotted line), pixels at distance smaller than 50 Mm from a filament (dashed-dotted line). Averages are computed over 1 year periods. The minimum activity period correspond to the left of the curves, and the maximum activity period to the right. Middle panel: same for D_uni. Lower panel: same for ∇B_pil.