Details of the coronal hole model. Initial profiles at the y = 0 plane are shown. Panel a: plasma number density measured in 10⁸ cm⁻³ (solid line) and magnetic field in G (dashed); panel b: characteristic speeds in the plasma in km s⁻¹, sound speed (solid line) and Alfvén speed (dashed), and magnetoacoustic (MAC) speed in the transverse direction (dotted); and panel c: plasma β^* values. See the exact values of parameters of the model in the text.