Blue sky catastrophe in systems with non-classical relaxation oscillations

The feasibility of a known blue-sky bifurcation in a class of three-dimensional singularly perturbed systems of ordinary differential equations with one fast and two slow variables is studied. A characteristic property of the considered systems is that they permit so-called nonclassic relaxation oscillations, that is, oscillations with slow components asymptotically close to time-discontinuous functions and a $\delta$-like fast component. Cases when blue-sky bifurcation leads to a relaxation cycle or stable two-dimensional torus are analyzed. Also the question of homoclinic structure emergence is considered.