Applied Mathematics Colloquium: Wave propagation and tidal dissipation in giant planets

Presenter: Christina Pontin (University of Leeds)

Title: Wave propagation and tidal dissipation in giant planets

Microsoft Teams Meeting

Summary:

Understanding the internal structures of planets and stars, and their effects on the propagation and tidal forcing of internal waves, is an active area of research. Recent gravity field measurements from Juno indicate a dilute core of heavy elements that occupies a significant fraction of Jupiter’s radius. Observations of the satellites of Jupiter and Saturn indicate higher tidal dissipation rates in these planets than standard theoretical models predict. This suggests there is an additional mechanism for tidal dissipation. I will present calculations to explore how internal wave propagation and tidal dissipation in a giant planet are affected by regions containing density gradients or staircase-like density structures. I will first present the dispersion relation for the free modes of a density staircase, which can be compared to that of interfacial and internal gravity waves. I will then show that there is enhanced wave transmission through a staircase when the incident wave is resonant with a free mode of the system. Finally, I will present calculations to study the resulting tidal dissipation and explore its dependence on the properties of the stratified layer.