Extrapolated non-force-free field of the active region at the start of the MHD simulation of the onset of the flare-making eruption. Panels a and b depict the side and top-view of the extrapolated MFLs with the magnetogram as the bottom boundary. The low-lying yellow MFLs represent the sheared arcade over the PIL. Panel c shows the distribution of the relative magnitude of the Lorentz force density in the computational domain, documenting the existence of the force at lower heights near the PIL. The Lorentz force density has the units of 1.5 × 10⁻⁸ dyne cm⁻³. Panel d illustrates the logarithmic variation of magnitude for the horizontally averaged magnetic field (B), the current density (J), and the Lorentz force density (L) with height, z. All of the values are normalised with respect to their maximum values.