Diagnostics of dielectronic processes in laser produced samarium plasma

Spatially-resolved time-integrated X-ray spectra of laser produced samarium plasma were recorded, in the spectral range from 7 to 10 Å. The spectrum of samarium is characterized by the prominent pattern of transitions 3d - nf (n = 4-7) belonging to Co-like (Sm ³⁵⁺), Ni-like (Sm ³⁴⁺) and Cu-like (Sm ³³⁺) ions. Spectral lines of Mn-like (Sm ³⁷⁺) to Zn-like (Sm ³²⁺) were identified. The appearance of these ionization stages as a function of distance from the target was measured. Transfer of the dominant ion stages to lower stages with increasing distance from the original target surface was demonstrated, probably indicating dielectronic recombination. The Hebrew University Lawrence Livermore Atomic Code was used to generate emission spectra for comparison with the experimental ones. A radiation-hydrodynamics code coupled to three non-Local Thermal Equilibrium ionization and equation of state models with different approaches for dielectronic processes was used to model the plasma. The simulated plasma ionization and electron densities and temperatures were found to be consistent with the experimental results.