Swift-Hohenberg Equation

∂u/∂t = [ε−(1+∇²)²]u − u³ — stripe & hexagon pattern selection

Parameters

State

ε: 0.30
Time: 0
u range: [, ]
Pattern:
Steps/s:

Theory

Swift-Hohenberg (1977):
u_t = [ε−(1+∇²)²]u − u³
Linear instability at q=1 for ε>0.

Pattern selection:
• ε small: stripes (rolls)
• Larger ε: hexagons, squares
• Defect dynamics: dislocations and grain boundaries coarsen over time

Critical mode: exp(i·r) with |q|=1 grows for ε>0. Nonlinearity selects amplitude:
|A|² = ε/3 (stripes)