Evolution of the height of the apex of the FR as extracted from the TMFM simulation (left panel) and from the zero-beta MHD relaxation (right panels). The blue dashed curve shows the results when applying the extraction scheme without ϵ prescription, while the red dashed curve depicts the FR height evolution with ϵ = 0.03 for the TMFM runs and ϵ = 0.04 for the MHD runs (see Sect. 3.1). The x-axis depicts the time normalised to the TMFM flux evolution (Sect. 3.4). The horizontal lines show 10% (grey) and 100% (black) of the domain height. The dotted vertical lines indicate the start- and endpoints of our analysis with (red) and without ϵ-prescription (blue), as described in Sect. 4.1.