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multiple time scale dynamics with two fast variables and one slow ...

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3.1 Bifurcation diagram of (3.6). Hopf bifurcations are shown in<br />

green, saddle-node of limit cycles (SNLC) are shown in blue <strong>and</strong><br />

GH indicates a generalized Hopf (or Bautin) bifurcation. The arrows<br />

indicate the side on which periodic orbits are generated at<br />

the Hopf bifurcation. The red curve shows (possible) homoclinic<br />

orbits; in fact, homoclinic orbits only exist to the left of the <strong>two</strong><br />

black dots (see Section 3.4.2). Only part of the parameter space<br />

is shown because of the symmetry (3.7). The homoclinic curve<br />

has been thickened to indicate that multipulse homoclinic orbits<br />

exist very close to single pulse <strong>one</strong>s (see [38]). . . . . . . . . . . . 66<br />

3.2 Sketch of the <strong>slow</strong> flow on the critical manifold C0 . . . . . . . . . 68<br />

3.3<br />

3.4<br />

Heteroclinic connections for equation (3.10) in parameter space. .<br />

Plot of the function R(h) for h∈(0,φ(<br />

72<br />

√ 3.5<br />

91<br />

)]. . . . . . . . . . . . . . . 15<br />

Geometry of periodic orbits in the (x1, x2)-<strong>variables</strong> of the 2-<br />

78<br />

variable <strong>slow</strong> subsystem (3.18). Note that here x2 = ǫ ¯x2 is<br />

shown. Orbits have been obtained by direct forward integration<br />

forǫ= 0.01. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79<br />

3.6 Hopf bifurcation at p≈0.083, s=1 <strong>and</strong>ǫ= 0.01. The critical<br />

manifold C0 is shown in red <strong>and</strong> periodic orbits are shown in<br />

blue. Only the first <strong>and</strong> the last critical manifold for the continuation<br />

run are shown; not all periodic orbits obtained during the<br />

continuation are displayed. . . . . . . . . . . . . . . . . . . . . . . 81<br />

3.7 Tracking of <strong>two</strong> generalized Hopf points (GH) in (p, s,ǫ)parameter<br />

space. Each point in the figure corresponds to a different<br />

value ofǫ. The point GHǫ 1 in 3.7(a) corresponds to the point<br />

shown as a square in Figure 3.1 <strong>and</strong> the point GHǫ 2 in 3.7(b) is<br />

further up on the left branch of the U-curve <strong>and</strong> is not displayed<br />

in Figure 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82<br />

3.8 Homoclinic orbits as level curves of H(x1, x2) for equation (3.12)<br />

<strong>with</strong> y= x∗ 3.9<br />

1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />

Heteroclinic connections for equation (3.22) in parameter space.<br />

84<br />

The red curve indicates left-to-right connections for y= x∗ 1 <strong>and</strong><br />

the blue curves indicate right-to-left connections for y= x∗ 1 + v<br />

<strong>with</strong> v=0.125, 0.12, 0.115 (from top to bottom). . . . . . . . . . . . 86<br />

3.10 Singular limit (ǫ= 0) of the C-curve is shown in blue <strong>and</strong> parts<br />

of several C-curves forǫ> 0 have been computed (red). . . . . . 88<br />

3.11 Strong “splitting”, marked by an arrow, of the unstable manifold<br />

Wu (q) (red) used in the calculation of the homoclinic C-curve for<br />

small values ofǫ. The critical manifold C0 is shown in blue. The<br />

spacing in s is 0.05 for both figures. . . . . . . . . . . . . . . . . . 89<br />

xii

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