Longitudinal wave propagation in an elastic isotopic laser-excited solid plate with atomic defect (vacancies, interstitials) generation is studied by the nonlocal continuum model. The nonlocal differential constitutive equations of Eringen are used in the formulations. The coupled governing equations for the dynamic of elastic displacement and atomic defect concentration fields are obtained. The frequency equations for the symmetrical and antisymmetrical motions of the plate are found and discussed. Explicit expressions for different characteristics of waves like phase velocity and attenuation (amplification) coefficients are derived. It is shown that coupling between the displacement and defect concentration fields affects the wave dispersion characteristics in the nonlocal elasticity. The dispersion curves of the elastic-diffusion instability are investigated for different pump parameters and larger wave numbers. 1. Introduction The studies on the interplay of strain field and defect concentration field are of importance in various branches of science and technology, particularly in the laser fast recrystallization, laser annealing, multipulse laser etching, and pulsed laser-assisted thin-film deposition. During the past years, several models for self-organization processes of ordered large-scale (strain-concentration) structures in an ensemble of interacting (through the strain field) atomic defects (interstitial atoms, vacancies) on the surface of the laser-irradiated solid half-space [1, 2] and in solid layers [3–6] have been considered using coupled evolution equations for the atomic defect concentration field and the classical (local) elasticity equations for the self-consistent displacement field of the medium. The formation of one-dimensional (1D) nonlinear localized deformational structures in metallic and semiconductor plates has been investigated taking into account the influence of temperature changes, geometrical dispersion due to the presence of the boundaries, and dispersions due to defect-elastic interaction and flexoelectricity [3]. Also, the conditions needed for clusters and periodic defect-deformation structures to emerge were found, and the characteristics of those structures—such as the period of periodic structure, and the spatial distributions of strain and defect concentration fields—were determined. The classical continuum elasticity, which is a scale-free theory, cannot predict the small size effects. At nanometer scales, size effects become prominent. The classical elasticity concept is inadequate for describing the
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