The performance of magnetic confinement fusion devices, such as tokamaks, is strongly influenced by the effectiveness of the magnetic field in holding heat and mass inside the plasma volume and away from solid walls. Research over the past 70 years has shown that turbulent transport across the confining magnetic field is the dominant process setting the gradients of all important thermodynamic quantities. Recent advances have revealed the key role which the formation and interaction of turbulent structures can play in generating plasma phases with often counter-intuitive phenomena, such as transport barriers or spontaneous rotation. The latter makes it clear that plasma flows can interact with turbulent fluctuations, leading to changes in the quality of global confinement. The most characteristic feature of all turbulent flows is spectral transfer, i.e. spreading fluctuation power over a wide range of physical scales. Zonal flows constitute a special case in the field of flow–turbulence interactions, since the mutual effects of turbulence and large-scale flows are of similar magnitude. In most turbulence simulations the plasma is observed to generate its own radially varying flow. Through spectral transfer, these flows can provide a transport-free reservoir of energy for turbulence that is thus benign to confinement. The exploration of the role of such nonlinear behaviour is at the forefront of present day studies in the theory and experiments of magnetic confinement research.