(a) Radial profiles of neutral hydrogen atoms along the flux rope propagation direction in the pre-CME corona (black line) and during the eruption at t = 14.5 min (blue line) and t = 19.7 min (red line). (b) Comparison between ionisation equilibrium and non-equilibrium ionisation cases at the same times, with labelled positions of the flux rope and CME front at different times. (c) Changes in relative abundance of neutral hydrogen at the same cuts and the same times.