Non-linear radial oscillations of neutron stars: Mode-coupling results

The non-linear behaviour of oscillation modes in compact stars is a topic of considerable current interest. Accurate numerical studies of such phenomena are likely to require powerful new approaches to both fluid and spacetime computations. We propose that a key ingredient of such methods will be the non-linear evolution of deviations from the background stationary equilibrium star. We investigate the feasibility of this approach by applying it to non-linear radial oscillations of a neutron star, and explore numerically various non-linear features of this problem, for a large range of amplitudes. Quadratic and higher order mode coupling and non-linear transfer of energy is demonstrated and analysed in detail.