Coronal quasi-steady state. Panel a: simulation snapshot of the plasma temperature upon the injection of a 1 mHz linearly polarised Alfvén wave, with an annotation describing the viewing angle along 125° at τ = 1000 min after the injection of the Alfvén wave. Panels b and c: out-of-plane v_ϕ velocity and the B_ϕ magnetic field components, respectively. The fluctuations induced in the density ρ from the quasi-steady values prior to the injection of the Alfvén wave are presented in panel d.