Lorentz Chaos - The 'Butterfly Effect'

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Homework Help Overview

The discussion revolves around the Lorentz system, specifically examining the dynamics of the system with parameters set to ##\sigma=10, b = \frac{8}{3}, r = 28##. The original poster attempts to demonstrate how to solve for ##y(t)## and ##z(t)## by analyzing the modified Lorentz system through the concept of Lyapunov exponents and the implications of chaos, particularly the 'butterfly effect'.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the stability of fixed points and the relationship between Lyapunov exponents and chaotic behavior. The original poster questions the implications of positive Lyapunov exponents on trajectories in phase space. There are requests for insights and help regarding the chaos aspect of the problem.

Discussion Status

The discussion is ongoing, with participants seeking clarification and assistance on specific aspects of chaos within the Lorentz system. While some attempts have been made to analyze the equations and fixed points, there is no explicit consensus or resolution yet.

Contextual Notes

Participants note that the stability of certain fixed points is conditional on the value of ##r##, specifically that points are only stable for ##1 < r < 25##. There is uncertainty regarding the specific requirements of the problem, particularly in the latter parts of the discussion.

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Homework Statement



Given the lorentz system for ##\sigma=10, b = \frac{8}{3}, r = 28##, and ##x(t)## from the first lorentz system, show that we can solve for y(t) and z(t) for the modified lorentz system by finding ##\dot E##.[/B]

2013_B1_Q3.png


Homework Equations

The Attempt at a Solution



I have found the 3 fixed points. They are at the origin ##(0,0,0)##, and ##C^{+} = \left( \sqrt{b(r-1)}, \sqrt{b(r-1)}, r-1 \right)## and ##C^{-} = \left(-\sqrt{b(r-1)}, -\sqrt{b(r-1)} , r-1 \right)##. For ##r = 28##, all three points are unstable.

It turns out that the points ##C^{+}, C^{-}## are only stable for ##1 < r < 25##.

For a dynamical system, the Lyapunov exponent ##\lambda## is related to the trajectory in phase space by
|\delta V(t) | = |\delta V_0| e^{\lambda t}
So does this mean that for ##\lambda > 0## these trajectories are replled from one unstable point to another unstable point? I think this is the 'butterfly effect' described somewhere.

Also, I have re-expressed the equations:
\dot e_x + \dot x = \sigma \left[ (e_y - e_x) + (y-x) \right]
\dot e_y + \dot y = rx - (e_y + y) - x(e_z + z)
\dot e_z + \dot z = x(e_y + y) - b(e_z + z)
\dot E = \frac{2}{\sigma} e_x \dot e_x + 2 e_y \dot e_y + 2 e_z \dot e_z

I'm not sure what the question wants..
 
Last edited:
any insight on last part?
 
any help on the chaos bit?
 
bumpp on chaos
 
butterfly bumpping
 
bump on lorentz chaos
 
Solved.
 

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