Maps of radial velocity (top-left), longitudinal velocity (top-right), density (bottom-left), and temperature (bottom-right) along the middle of the cylinder for the base model − 171 (see Sect. 2.4 for more details). The snapshot is taken at one-third of the mode period. The black and white dashed lines in the top panels denote the 4 different line-of-sight angles considered: 0°,30°,45°, and 60°. For each angle two rays along the line-of-sight are plotted, one passing through a node of the radial velocity (left ray of the pair) and one passing through an anti-node of the same quantity (right ray of the pair). The different pixel sizes considered are shown centred at a node: “0R” (=25 km), “1R” = 1 Mm, “2R” = 2 Mm, “3R” = 3 Mm. In the base model, 1R, 2R, and 3R correspond roughly to ℓ/3,2ℓ/3, and ℓ, respectively, where ℓ denotes the wavelength of the mode.