Numerical simulation of thermo-acoustic processes induced by high current ion beams in thin films

Modern experimental data on the ion treatment of solid surfaces need a theoretical investigation of thermoelastic processes taking place in patterns. Mathematical simulation of the latter requires exact physical description of the energy deposition both in time and space. In this work we try to come to a realistic model of the thermoelastic processes in materials which are under the influence of high intensity ion bombardment. To this end a model of time dependent spatial dynamics of energy deposition in thin films, corresponding to the existing ion pulse explosion sources, is developed. It is based on a formula: Q(x,t)=Pf(t-τ(x))g(x)Θ(t-τ(x)), where P is the density of deposited power per a surface unit, f(t) describes a time dependence of accelerator current, Ι(t)=Ιmaxf(t), and τ(x), g(x) denote retardation time and dose distribution in depth, respectively, which are found with account of the existing data on stopping power of ions in matter. Dependence of the acoustic material treatment on the source characteristics is considered. (author)