Modelling tidal waves and their nonlinear (magnetised) coupling in stars and planets

Aurélie Astoul (IRAP)

Tidal interactions are a key driver of the orbital and rotational evolution of close stellar and (exo-)planetary systems. In stars and gaseous planets, the tidal response can manifest as tidal waves, whose energy is expected to be significantly dissipated and allows for an efficient redistribution of angular momentum within the system. In very close ones, such as Hot-Jupiter or close stellar binary systems, tidal waves are sensitive to nonlinear effects arising from the nonlinear (advection) terms in the governing wave equations. In this vein, I will present nonlinear (magneto-) hydrodynamical simulations of tidally-excited waves in spherical convective (or radiative) shells. I will explain how tidal waves can trigger and interact with differential rotation, and can even modify the amplitude and topology of magnetic fields, sometimes through fluid or magnetic instabilities. Furthermore, the coupling between tidal waves and their environment can substantially modify tidal dissipation rates from prior linear predictions, which is of paramount importance when modelling, for example, the dynamical evolution of the architecture of a two (or n-) body system.