The stopping power of warm dense matter (WDM) is estimated by means of the individual contributions of free electrons and bound electrons existing in this special kind of matter, located between classical and degenerate plasmas. For free electrons, the dielectric formalism, well described in our studies, is used to estimate the free electron stopping power. For bound electrons, the mean excitation energy of ions is used. Excitation energies are obtained through atomic calculations of the whole atom or, shell by shell in order to estimate their stopping power. Influence of temperature and density is analyzed in case of an impinging projectile. This influence becomes important for low projectile velocities and is negligible for high ones. Using free and bound electron analysis, the stopping power of an extended WDM is inferred from a dynamical calculation of energy transferred from the projectile to the plasma, where the stopping range is calculated. Finally, this theoretical framework is used to study a typical plasma density profile of a WDM heated by lasers.

In this work, we analyze the thermodynamic states of the helium plasma and their influence on the stopping power calculations which are needed for obtaining the energy loss of the iron beams traversing them. The analysis is made in ranges of plasma free electron densities (10 15 -10 19 cm À3 ) and temperatures (1-10 eV) of experiments with iron beams at 6 and 4.3 MeV/u energies. For this purpose, we use Saha-Boltzmann equations for local thermal equilibrium (LTE) and a collisionalradiative model for non-local thermal equilibrium (NLTE) in steady-state situation implemented in a computer code. For the highest temperatures and free electron densities, LTE and NLTE models provide quite similar results for the average ionization and ion abundances. When the opacity effects are taken into account in the NLTE simulations, the optically thick simulations provide fairly similar results to those of the LTE model. The plasma thermodynamic states have a direct impact on the calculation of the energy loss. The differences on the plasma stopping power between considering it in LTE or in NLTE may entail a 10% of the total stopping for the experiments analyzed in the electron density region of 10 18 -10 19 cm À3 . These differences can be around 27% for plasmas with smaller electron density of 10 17 cm À3 and around 42% for plasmas with an electron density of 10 15 cm À3 . New experiments would be appreciated to be made in a future to corroborate the latest calculations.

In this work, the stopping power of a partially ionized helium plasma due to its free and bound electrons is analyzed for an electron temperature and density in which local thermal equilibrium (LTE) or non-local thermal equilibrium (NLTE) regimes can be possible. In particular by means of collisional-radiative models, the average ionization of the plasma as well as the abundances of different helium species (HeI, HeII, and HeIII) are analyzed in both LTE and NLTE thermodynamic states. The influence of this ionization and of the different ion abundances on the stopping power of the helium plasma is shown to be quite significant. Finally, our theoretical model is compared with experimental results on slowing down of swift argon ions in helium plasma.

In this work, an expression for the bound electron stopping power of partially ionized highly energetic ions for partially ionized plasmas in the context of the Bethe approximation, in both local thermodynamic equilibrium and nonequilibrium, is presented and studied. The mean excitation energy of the stopping power incorporates a detailed description of the bound electron states of both the ion beam and plasma under different thermodynamic regimes. In the analysis carried out, we focus our attention on fully stripped ion beams in partially ionized aluminum plasmas. The temperature and electron density ranges considered were 4–100 eV and 1016–1022 cm−3, respectively.

In this paper, stopping power as a result of free and bound electrons in a fully or partially ionized plasma will be studied. The free electron stopping power will be analyzed using the dielectric formalism, whereas bound electron stopping power will be calculated through atomic approximations. The data used for the calculations came from experiments in which hydrogen and argon hot plasmas are shot with up to 10 MeV protons. Plasma ion densities are ranged between 1019 and 1022 cm−3 and electron temperatures from 10 to 300 eV. In this experimental setup, the data show a regime of reduced stopping power that will be reproduced early exactly by our theoretical model.