The interfacial f mode in a spherical solar model

The solar f modes are a branch of oscillations characterised by a close correspondence between their measured dispersion relation and that predicted for a pure surface-gravity wave: ! 2 = gk where g is the surface gravity of the Sun. However, there is now substantial evidence for deviations from this simple behaviour. We consider the hypothesis of Rosenthal and Gough (1994) that the f modes are characterised better as an interfacial wave propagating at the chromosphere-corona transition. Using a standard solar-interior model, a semi-empirical atmospheric model, and a parameterised transition-region model as our equilibrium state, we solve the linearised oscillation equations for the interfacial f mode. We nd that the frequencies of the interfacial f mode diier from those of the classical f mode only at very high degree. We conclude that the interfacial f-mode theory may be the correct explanation for the very high degree data, but that some other mechanism is required to explain the lower degree data.