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Computer Algebra Recipes

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328 CHAPTER 8. NONLINEAR DIAGNOSTIC TOOLS<br />

q1<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

–0.2<br />

–0.4<br />

–0.6<br />

–0.5<br />

0<br />

p2<br />

H = .1250000000;<br />

0.6 0.4 0.2 0 –0.2<br />

q2<br />

–0.4<br />

–0.6<br />

Figure 8.7: Chaotic trajectory for E = 1<br />

8 .<br />

A great deal of mathematics research has gone into understanding the onset<br />

of chaos for the nonlinear Henon{Heiles ODE system. The interested<br />

reader is referred to the nonlinear dynamics texts by Jackson [Jac90] and by<br />

Hilborn [Hil94].<br />

PROBLEMS:<br />

Problem 8-6: A di®erent potential<br />

Replace the potential in the text recipe with<br />

V = 1<br />

2 q2 1<br />

1 +<br />

2 q2 2 + q4 1 q2 ¡ 1<br />

4 q3 2 :<br />

(a) Execute the modi¯ed recipe with E =1=16 and initial conditions as in<br />

the text recipe. Discuss the resulting plots.<br />

(b) Explore other initial conditions for the same total energy as in part (a).<br />

Discuss the results.<br />

(c) Explore what happens as the energy is increased with the same initial<br />

conditions as in part (a). Discuss the results.<br />

(d) Explore other potential energy functions and discuss the results.<br />

Problem 8-7: Toda potential<br />

The Toda potential [Jac90] is given by<br />

V = 1<br />

μ<br />

e<br />

3<br />

(q2 + p 3 q1) (q2 + e<br />

¡ p <br />

3 q1) (¡2 q2)<br />

+ e ¡ 1:<br />

(a) Create two- and three-dimensional contour plots of V , choosing suitable<br />

potential energy contours and viewing ranges.

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