Driven inertial oscillations in spherical shells

The how of a fluid in a rapidly rotating spherical shell whose rotation rat e is modulated sinusoidally in time is simulated numerically. Different ine rtial modes are excited as the modulation frequency is varied. The inertial modes are structured by internal layers. Internal layers are reflected at the boundaries such that at certain modulation frequencies, the layers are focused onto "attractors" after multiple reflections. The geometric propert ies of these attractors and their relevance for the response of the fluid i s investigated. [S1063-651X(99)06402-8].