Investigation of the flux rope eruption mechanisms. The top row shows the field lines colored based on the scaled NLFFF coefficient, the middle row the decay index and the bottom row the twist number (see the text for the explanation). The results are shown from left to right for initializing the zero-β MHD simulation with the TMFM snapshot at t₋₂₄, t₋₁₂, and t_ref. The bottom part of the figures shows the magnetogram, which is the bottom boundary of our simulations. The results are shown here only for the 1.5 × Ω_opt. In the bottom right panel the subdomain enclosing the main flux system is indicated by the black box.