Fig. 15

Two-parameter bifurcation diagram of the fast system of Equations 9a-9c in the $(u,r_x)$-plane. This includes loci of saddle-nodes of fixed points SNf, Hopf bifurcations H, saddle-nodes of periodic orbits SNp, and homoclinic bifurcations HC. There are three labeled codimension-2 bifurcations: a Bogdanov-Takens bifurcation BT at $(u,r_x)\simeq (-3.325,-3.029)$, a Bautin bifurcation B at $(u,r_x)\simeq (-0.4945,-4.740)$, and a SNpHC at $(u,r_x)\simeq (1.364,-5.203)$. Plotting conventions follow Figure 6.