Radiation influence on the plasma atomic kinetics and spectra in experiments on radiative shock waves

Abstract

Radiative shocks waves are among of the most interesting astrophysical phenomena and due to their relevance, many laboratory experiments, using high-power lasers, have been performed to achieve a better understanding of them. The radiation emitted by the shock front can heat and ionize the pre-shock medium leading to the formation of radiative precursors, which are relevant in these phenomena since they absorb part of the radiation emitted by the shock front and becomes a strong source of radiation emission. The plasma in the precursor can be considered as a photoionized plasma in which the external radiation field plays a dominant role in the atomic kinetics behavior. A numerical study of the influence of the radiation field on the ion populations, radiative properties and atomic spectra of radiative precursors in radiative shocks generated in two laboratory experiments is presented. For the numerical simulations, three types of collisional-radiative models have been used. In the first one, the radiation induced processes are not included. In the second type, the radiative atomic processes induced by plasma self-absorption are considered. Finally, the radiative processes induced by both the external radiation field and the plasma self-absorption are included. The results obtained show the noticeable influence of the radiation field on the plasma properties analyzed.