Quantities from the MHD model of the unsheared arcade (Sect. 4.1), at a coronal height of x = 25 Mm, at the time of the first density peak (t = 150 s). Left-hand panel: gas pressure (dashed line), magnetic pressure (solid line), and total pressure (dash-dotted line) as functions of position across the arcade. We note that the gas pressure has been offset by 398.4 × 10⁻¹ Pa in the pressure plot. Right-hand panel: j_z component of the current current density.