Abstract:

Computational methods are used to investigate the effects of fluid ompressibility on the frequencies of the inertial modes of the Earth’s fluid core. The 3PD (the three potential description) is applied to two models of compressible fluid spheres, for one of which the dilatation vanishes, in order to study these modes. We show that compressibility may have a significant effect on some of the modal frequencies. Using the shape of the displacement eigenfunctions of a fluid sphere we also infer which modes of a sphere may have counterparts in a spherical shell. We then give a few examples of the inertial modes of a compressible fluid shell proportional to the Earth’s fluid core.