Slices of the G9 galaxy, from left to right: gas density, gas velocity, sum of CR and thermal pressures, and ratio of CR to thermal pressure, seen edge-on at 250 Myr for the different simulations as indicated in the panels (one model per row). See Fig. 1 for the other runs. In the noCR case, a low density wind is generated with velocities of a few hundred km s⁻¹; in the Advection model, the disc is puffed up but the wind is much weaker. When adding CR diffusion, the wind is 10 times denser with velocities similar to noCR case. The sum of CR and thermal pressures increases by 2 orders of magnitude and mainly consists of CR pressure. With CR streaming, the morphology is similar to the Advection case, but with a mild wind.