The laser initiation of energetic materials doped with metal nanoparticles having oxide shell explosive decomposition

The work is devoted to the development of the model describing laser initiation composite materials being an explosive matrix with metal nanoparticles covered with oxide shell. The model considers the oxide shell as a dielectric that does not absorb light. The example of aluminum nanoparticles covered with alumina is the main one in the paper. The model describes the thermal transfer in the system metal core-oxide shell- explosive material, exothermic decomposition of the explosive considered as a one-step reaction with Arrhe- nius dependence on the rate on temperature, and light absorption of the core-shell interface. The model is written as a system of the equations and respective computer program is developed. The semi-quantitative analysis of the model using the typical thickness of the heated layer of the matrix is performed. It is shown that the radius of the nanoparticle heated most is proportional to the thickness of the heated layer of the ex- plosive matrix as in the previous versions of the model though the coefficient depends on the oxide shell thickness. The numerical analysis is done. The dependencies of critical energy density on the oxide shell thickness at constant nanoparticle’s radius and on the radius at constant shell thickness are calculated. The dependence on radius shows the existence of the optimal particle minimizing the critical energy density whose radius depends on the shell thickness.