Spatial instabilities and dislocation-loop ordering in irradiated materials

The formation of inhomogeneous distributions of vacancy loops in irradiated materials is discussed in the framework of a dynamical model based on the rate theory of radiation damage. Dislocation structures are associated with dynamical instabilities due to the competition between defect motion and interactions. The dependence of the critical wavelength of the microstructures on material variables, such as the displacement-damage rate, network-dislocation density, or temperature, is obtained. The postbifurcation analysis is performed in the weakly nonlinear regime, where the selection and stability properties of three-dimensional structures are investigated.