Elastic Interface Depinning

An elastic line driven through a disordered medium. Below the depinning threshold Fc the interface is pinned. Above Fc it moves with velocity v ~ (F−Fc)β — a non-equilibrium critical transition.

Interface (blue line) in disorder landscape (yellow = strong pinning)
Velocity v vs driving force F (depinning curve)

Parameters

v = 0
Pinned
Equation of motion:
∂_t h = c∇²h + F + η(x,h)

Depinning exponent β≈0.625 (1D)
Roughness ζ≈1.25 (1D)

Applications: domain walls, crack fronts, contact lines, vortex lattices