From left to right and top to bottom: global solar-disc maps of attractive Lagrangian coherent structures imaged as ridges of maxima of the backward-in-time FTLE field, for different integration times of 1, 2, 3 and 6 days respectively. Increasingly small apodising windows are used for longer time integrations (from 60° opening for T = 24 h to 23.5° opening for T = 144 h) to avoid contamination by imprecise velocity measurements at the limb (see discussion in Sect. 2).