REACTION-
DIFFUSION
PATTERNS
Animations from a numerical simulation of a time dependent reaction diffusion model in two space dimensions. The red and purple colors represent the two stable uniform states of this bistable system (eg. a high and low chemical concentrations).
More details of the FitzHugh-Nagumo model, parameters, and numerical
methods used can be found in the references.
- Labyrinthine pattern
- An initial stripe is unstable to transverse perturbations
and grows. The stripe meanders and undergoes tip-splitting
until a final stationary labyrinthine pattern is reached.
- Spiral breakup
- A spiral wave, intially computed in a stable parameter
regime, breaks and a new pattern emerges where new spiral
waves are continuously created and destroyed.
- Spiral breakup 2
- A spiral wave, intially computed in a stable parameter
regime, breaks and a new pattern emerges where new spiral
waves are continuously created and destroyed.
- Spiral turbulence
- An almost planar pluse is unstable to transverse perturbations.
Cusps form along the front line and nucleate pairs of new
spiral waves. The spirals are unstable and break,
creating new spiral pairs.
- Spot splitting
- A small spot grows, splits into two spots, and
eventually fills the entire domain with a disconnected
labyrinthine pattern
- Spot splitting 2
- A small spot grows, splits into two spots, and
eventually fills the entire domain with a disconnected
oscillating labyrinthine pattern. The
long-time behavior of this pattern is unknown.
- Spiral breakup by an external advective field
- A spiral wave is subjected to a weak hexagonal advective field
and breaks to form many new spiral tips.
References
Aric Hagberg <aric@lanl.gov>
Last modified: Tue Mar 25 18:12:20 MST 1997