Snapshot of the three main global variables in the simulation. Panel a: number density in cm⁻³. Panel b: vertical velocity normalized with respect to the sound speed. For better visibility of the midplane region, we show only an extent of ± 53° with respect to the midplane. Panel c: vertical kinetic energy in g cm⁻¹ s⁻². Overplotted are contour solid lines where the column density of the EUV-heated region is defined by Σ_r =10¹⁹ cm⁻² (in purple), and the column density of the X-rays/FUV-heated boundary layer is defined by Σ_r = 10²² cm⁻² (in dark green). The number density of hydrogen nuclei at the H/H⁺ boundary is ~10⁹ cm⁻³ and at the X-rays/FUV-heated layer is ~10¹² cm⁻³.