Comparison of results with different cosmic ray coupling strength. The cosmic ray diffusion coefficient is defined as . Here, we compare solutions for different η of the cases with cooling in Fig. 2. Left column: cooling is “ON” and wave damping is “OFF” (δ_c = 0.1, δ⁺ = 0). Right column: both cooling and wave damping are “ON” (δ_c = 0.1, δ⁺ = 0.1). Four different cases are shown, (1) η = 5 (dotted line), (2) η = 2 (dashed line), (3) η = 1 (dot-dashed line), and (4) η = 0.5 (solid line). All other parameters are the same as Fig. 2, except that D_cb is adjusted to produce transonic solutions.