Power spectra of the spatial fluctuations of the unsigned magnetic flux density in the IN regions, on a log−log scale. Top panel: at the center of the disk; middle panel: at high latitude in the southern hemisphere; and bottom panel: at high latitude in the northern hemisphere. The bars show the ±σ intervals. Blue lines: in 2014; red lines: in 2008; and orange lines: in 2009. Dashed (full) lines: from the FeI 630.15 nm (FeI 630.25 nm) line.