Post-doctoral scholar David Cebron will give a special seminar Thursday, November 29th, at 2pm in Geology 3814. The talk is entitled “Inertial waves & instabilities in planetary and stellar fluid interiors.”
Most astrophysical bodies such as gaseous planets, stars or the Earth liquid core are rapidly rotating fluids which allow the propagation of inertial waves. These waves are excited by natural mechanical forcings (tides, precession, libration) always present in such systems. Forcings can excite one particular wave (direct resonance) or can couple waves via parametric resonances called inertial instabilities. These vigorous flows may play an important role for the heat transport or can be an alternative to the classical thermo-chemical model for the generation of planetary and stellar magnetic fields (dynamo effect).
After an introduction on the geo-/astrophysical context of these inertial waves, he will focus on tidal forcing and present numerical simulations of the elliptical instability in an ellipsoidal geometry. Then, he will describe the influence of different natural complexities such as the oblateness, the presence of convective or stratified flows. He will also show that libration of sychronized bodies (e.g. the Earth-Moon system) can similarly lead to resonances of inertial waves. Finally, He will consider the possible role of these resonances in magnetic field generation (dynamo effect) using MHD simulations, and he will present the first free-surface simulations (SPH code, Gerris code) dedicated to the study of these flows in gaseous bodies.