Expansion of laser-ablated two-component plume with disparate masses

Abstract

Laser ablation of boron and tungsten is studied theoretically. The effect of disparate masses of boron and tungsten on parameters of the laser-ablated plasma plume is studied. A theoretical model is applied, which describes both the target heating and formation of the plasma and its expansion. Calculations are made for the third harmonic of a nanosecond Nd:YAG laser. The calculated distributions of plasma temperature, velocity and electron density in the early phase of expansion show that the plasma temperature is higher in the case of heavier tungsten, but the velocity is higher in the case of lighter boron, which is in agreement with experimental findings. In addition, the absorption coefficient of 355 nm radiation, the emission coefficient, the mass density and heat capacity of boron and tungsten plasma are compared.