Intensity levels of MTI turbulence. Dashed line: root-mean square of the 3D turbulent velocity field as a function of the radius in the ICM. Full line: root-mean square of the 3D turbulent line-of-sight velocity (top) and temperature (bottom) fluctuations. Dotted line: same but for the estimated 2D projected quantities after integration along the line of sight. The dash-dotted black lines are X-IFU detectability limits (determined in Sect. 4) for a typical 2-Ms observation of a Perseus-like cluster at 0.25R₂₀₀. The colour encoding follows Fig. 1.