Numerical MHD separator model (MHS2); Final electron and proton positions coloured by particle energy gain, based on different snapshots during the MHD experiment. Each row depicts a different snapshot, for electron (top) and proton (bottom) positions and each is overlaid with the corresponding isosurface of critical current, j_crit (in green) for that snapshot. Black arrows indicate typical final positions of accelerated particles, as a guide; these locations most strongly reflect changes in particle behaviour as experiment evolves. Topological features seen here are coloured in an identical manner to those identified in Fig. 1 and previous experiments. For reference, b_scl = 10 G, l_scl = 1 Mm, and t_scl = 20 s for these orbit simulations.