Influence of absorption mechanisms on laser-induced plasma plume

In modelling laser-induced plasma plume formation, the proper description of laser absorption in the plasma plays an important role. In the present model, absorption is described by means of three different mechanisms: inverse bremsstrahlung (IB), photoionization (PI) and absorption by small condensed clusters. Numerical solutions of the model are given for KrF laser beam irradiation (wavelength λ=248 nm) impinging on a nickel target at various fluences. The influence of particular absorption mechanisms on the absorbed laser beam energy in the plasma plume during the pulse is shown for different fluences. Using all three absorption mechanisms, the calculated plasma properties show good agreement with the experimental results of other authors.