Chaos in a coupled oscillators system with widely spaced frequencies and energy-preserving non-linearity

This paper is a sequel to Tuwankotta [Widely separated frequencies in coupled oscillators with energy-preserving nonlinearity, Physica D 182 (2003) 125-149.], where a system of coupled oscillators with widely separated frequencies and energy-preserving quadratic non-linearity is studied. We analyze the system for a different set of parameter values compared with those in Tuwankotta [Widely separated frequencies in coupled oscillators with energy-preserving nonlinearity, Physica D 182 (2003) 125-149.]. In this set of parameters, the manifold of equilibria are non-compact. This turns out to have an interesting consequence to the dynamics. Numerically, we found interesting bifurcations and dynamics such as torus (Neimark-Sacker) bifurcation, chaos and heteroclinic-like behavior. The heteroclinic-like behavior is of particular interest since it is related to the regime behavior of the atmospheric flow which motivates the analysis in Tuwankotta [Widely separated frequencies in coupled oscillators with energy-preserving nonlinearity, Physica D 182 (2003) 125-149.] and this paper.