Thermal profile of the neutral fluid, as computed for a CJ‐type shock wave of speed v_s= 20 km s⁻¹, propagating into molecular gas of density n_H≈ 2n(H₂) +n(H) = 10⁴ cm⁻³, with an initial transverse magnetic field strength B= 100 μG. The independent variable in this figure is the flow time of the ionized fluid, t_i. The dynamical age was varied in the range 500 ≤t≤ 5000 yr. The corresponding C‐type model (i.e. the steady‐state solution, attained by t≈ 10 000 yr) is shown for comparison purposes. As the shock wave ages, the J‐discontinuity moves to the right, becoming progressively weaker as equilibrium is approached.