The influence of transverse perturbations on the motion of an edge dislocation was studied using the averaged Lagrangian of the Ritz–Whitham type. The dislocation was described by the Frenkel–Kontorova model with inclusion of elastic anharmonicity and lattice discreteness (acoustic dispersion). The quadratic anharmonicity and acoustic dispersion were shown to promote self-focusing of the dislocation and microcrack formation. Under certain conditions, cubic anharmonicity could stabilize transverse compression of the dislocation, which could bring about the development of "crowdion droplets."

Effects of Transverse Perturbations on the Motion of an Edge Dislocation. A.N.Bugaĭ, S.V.Sazonov: Physics of the Solid State, 2005, 47[4], 646-51