Abstract

I make the claim that the outer core of the Earth, a rapidly-rotating, electrically-conducting ocean vigorously stirred by convective upwellings, is a breeding ground for a diverse zoo of wave motions. These are highly dispersive (since propagation velocity depends on wavelength), anisotropic (due to the rotation axis and local magnetic field direction), caustical (or “self-focussing”), heterogeneous (due to a spatially-varying field), dissipative (owing to the field’s diffusive nature), and non-linear (necessarily, if they are to alter field topology). I address all but one of these peculiarities, unearthing some interesting phenomena along the way, and perhaps opening a small window onto planetary core dynamics – specifically the mechanisms which may encourage dynamo action.