The evolution of the nanoscale dissipative structures in a distribution of defects within the isothermally irradiated f.c.c. crystal

A kinetic model for the influence of external noises such as fluctuations of the \nvacancies’ generation rate and inhomogeneity of irradiated f.c.c. crystal on the \nformation of nanoscale modulated dissipative structure in a spatial distribution of \nvacancies is considered. The generation rate of vacancies all over the sites and a \ndensity of their dislocation-type sinks are modelled as independent random uniform \nstationary fields and with certain defined parameters of fluctuation correlations— \nspatial and temporal ones. Such stochastic fields can induce a spatial redistribution \nof vacancies that can lead to their density stationary uniform field or \nstochastic one. By the average value and correlation functions of these fluctuations, \nthe conditions are determined for interacting fluctuations of the vacancies’ \ndensity, under which this homogeneous random field becomes unstable in relation \nto the stochastic field with a spatially periodic mean distribution of vacancies’ \ndensity. For instance, with f.c.c. nickel as a model of the irradiated functional \nmaterial, the temperature dependence of spatial period d(T) of the modulated \ndissipative structure of vacancies’ subsystem in f.c.c. crystal is numerically \nforecasted and analysed, taking into account the total (‘electrochemical’ + ‘straininduced’) \ninteraction between vacancies. Such d(T)-dependence is also determined \nby the kinetic characteristics of vacancies’ redistribution.