Solution of the radiative transfer equation in an absorbing and scattering Nd:YAG laser-induced plume

Abstract

We analyze the scattering effect in a laser-induced plasma plume in the case of a Nd:YAG laser welding process using a discrete ordinate scheme and the radiative transfer equation. The optical properties of plume vapors from stainless steel are analyzed at various temperatures as different parameters are varied (laser wavelength, plasma pressure and composition, type of shielding gas). The scattering coefficients and the phase function due to the presence of small particles in the plume are calculated using the Mie theory for different particle diameters and several densities of particles in the medium. With our model we estimate the temperature in the plasma plume.