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1976 The Rössler system

Christophe LETELLIER
11/01/2008
Otto E. Rössler

The system

The most popular example of the a simple folding remains the Rössler system proposed in 1976 [1] :

\[\left\{ \begin{array}{l} \dot{x }= -y-z \\[0.1cm] \dot{y} = x + ay \\[0.1cm] \dot{z} = b + z(x-c) \end{array} \right.\]

It is characterized by a first-return map with a differentiable critical point separating the increasing and decreasing branches. The Rössler attractor is observed with parameter values \(a=0.420\), \(b=2\) and \(c=4\).

(a) Folded chaos solution to the Rössler system.
(b) First-return map to a Poincaré section.

Fig. 1 : Spiral chaos solution to the Rössler system.

Rössler called this simple stretched and folded ribbon, the spiral chaos. He already sketch the structure of the attractor with a paper model as shown in Fig. 2 [2].

Fig. 2 : The "three-dimensional blender".
\(\rightarrow\) = trajectories entering the structure from the outside ; 1, 2 = half cross-section (demonstrating the "mixing transformation" that occurs), e = entry point of some arbitrarily chosen trajectory, r = reentry point of the same trajectory after one cycle. \(\uparrow\)= "horseshoe map", a.sl. = allowed slit.

For other parameter values, a more developed chaos is produced. The first-return map to a Poincaré section has now many monotonic branches as shown in Fig. 3. Rössler named that type of chaos, the funnel chaos. Its topology has been investigated by Letellier et al [3]. The spiral chaotic attractor corresponds to a phase coherent attractor while the funnel type is phase incoherent [4].

[1O. E. Rössler, An equation for continuous chaos, Physics Letters A, 57 (5), 397-398, 1976.

[2O. E. Rössler, Chaotic behavior in simple reaction system, Zeitscrift für Naturforschung A, 31 (3-4), 259-264, 1976.

[3C. Letellier, P. Dutertre & B. Maheu, Unstable periodic orbits and templates of the Rössler system : toward a systematic topological characterization, Chaos, 5 (1), 271-282, 1995.

[4J. D. Farmer, J. P. Crutchfield, H. Fröling, N. H. Packard & R. S. Shaw, Power spectra and mixing properties of strange attractors. Annals of the New York Academy of Sciences, 357, 453-472, 1980.

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