Nonlinear Dynamics of Distorted Astrophysical Discs: Warps and All

The classical perspective of astrophysical discs models them as being flat, circular and coplanar. However, a wealth of observational evidence has highlighted the ubiquity of warped geometries in a variety of contexts. This has motivated theoretical efforts to explain the origins of such distortions and understand their ensuing dynamical evolution. Despite marked progress, a complete theory remains elusive, particularly in the observationally relevant regime of large warp amplitudes wherein nonlinear effects and hydrodynamic instabilities significantly modify the warp evolution.

In this talk I will take you down this warped and winding path as I introduce a novel analytical ‘ring’ model for understanding the fundamental distorted dynamics. Our simplifying assumptions characterise the activation of extreme compressive motions for the first time, which are an essential feature for sufficiently large warp amplitudes. I will then turn towards local numerical experiments which reintroduce all hydrodynamical degrees of freedom. This will reveal the feedback of small-scale hydrodynamic turbulence on the bulk warping motions and highlight the rich range of scales intrinsic to the detailed evolution. 

If I have time at the end, I will briefly introduce the institute to some of my other interests regards dust-gas interactions, the dynamics of debris discs and eccentric planet-disc interactions.