Internal and Inertial Wave Attractors: A Review

This paper presents a review of theoretical, experimental, and numerical studies of geometric attractors of internal and/or inertial waves in a stratified and/or rotating fluid. The dispersion relation for such waves defines the relationship between the frequency and direction of their propagation, but does not contain a length scale. A consequence of the dispersion relation is energy focusing due to wave reflection from sloping walls. In a limited volume of fluid, focusing leads to the concentration of wave energy near closed geometrical configurations called wave attractors. The evolution of the concept of wave attractors from ray-theory predictions to observations of wave turbulence in physical and numerical experiments is described.