Vertical initial profiles. a) Density (ρ, green solid line) and temperature (T, red solid line) as function of height. b) Gas pressure (p, blue solid line) and horizontal average of plasma β (< β> _H, black solid line). The grey area covers the minimum and the maximum values of β for each height. The horizontal grey line indicates β = 1. c) Initial forces: horizontal average of the vertical Lorentz force (< LF_z> _H, black solid line), gas pressure gradient ((∇p)_z, blue solid line) and gravity (ρg, dashed yellow line). The vertical dashed grey line indicates the division between uniform and stretched grid in z.