Mtm. Koper, BIFURCATIONS OF MIXED-MODE OSCILLATIONS IN A 3-VARIABLE AUTONOMOUS VANDERPOL-DUFFING MODEL WITH A CROSS-SHAPED PHASE-DIAGRAM, Physica. D, 80(1-2), 1995, pp. 72-94
The bifurcation structure of a three-variable Van der Pol-Duffing-type
model is studied in some detail, with special attention to the mixed-
mode solutions, a type of complex periodic behavior frequently encount
ered in oscillating chemical reactions. The mixed-mode oscillations in
the model occur close to two Hopf bifurcations, which are arranged wi
th the saddle-node bifurcations in a so-called cross-shaped phase diag
ram, a bifurcation diagram also typical for chemical reactions. The mi
xed-mode oscillations are shown to lie on isolated bifurcation curves,
which are all born in a single codimension-two bifurcation known as t
he neutrally twisted homoclinic orbit or inclination switch. With the
introduction of an additional slow time scale, the same model can exhi
bit more complex mixed-mode oscillations and torus bifurcations.