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 the present work, classical electron–ion scattering, Coulomb logarithm, and stopping power are studied taking into account the quantum mechanical diffraction effect and the dynamic screening effect separately and together. The inclusion of the quantum diffraction effect is realized at the same level as the well-known first-order gradient correction in the extended Thomas–Fermi theory. In order to take the effect of dynamic screening into account, the model suggested by Grabowski et al. in 2013 is used. Scattering as well as stopping power of the external electron (ion) beam by plasma ions (electrons) and scattering of the plasma's own electrons (ions) by plasma ions (electrons) are considered differently. In the first case, it is found that in the limit of the non-ideal plasma with a plasma parameter Γ → 1, the effects of quantum diffraction and dynamic screening partially compensate each other. In the second case, the dynamic screening enlarges scattering cross-section, Coulomb logarithm, and stopping power, whereas the quantum diffraction reduces their values. Comparisons with the results of other theoretical methods and computer simulations indicate that the model used in this work gives a good description of the stopping power for projectile velocities $v\,{\rm \lesssim}\, 1.5 v_{{\rm th}}$, where vth is the thermal velocity of the plasma electrons.

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.

The precise estimation of stopping power is crucial to predict the beam energy loss in the target for heavy-ion fusion and heavy-ion-driven high-energy density physics experiments. The electromagnetic shock wave has been proposed to generate a well-defined atomic hydrogen target for the stopping power measurement with dissociation effects. We measured the angular distribution profile of the discharge plasma and the plasma velocity in the electromagnetic shock tube by high-speed framing cameras. To improve the uniformity of the discharge plasma and the velocity, an external magnetic field was applied in the electromagnetic shock tube. The plasma velocity was up to approximately 40 km/s for an initial hydrogen gas pressure of 100 Pa and the velocity decreased with the initial pressure and the propagation length. The framing cameras showed that angular distributions of the discharge plasmas were not uniform and the initial angular distributions were important for the development of plasma profiles. The interaction of the plasma with the external magnetic field was estimated using the ratio of the plasma dynamic pressure to the magnetic pressure. The estimations offer more magnetic fields to improve the discharge uniformity due to the interaction.

A two-dimensional particle-in-cell (PIC) simulation is carried out to study the wakefield and stopping power for a hydrogen ion beam pulse with low drift velocity propagation in hydrogen plasmas. The plasma is assumed to be collisionless, uniform, non-magnetized, and in a steady state. Both the pulse ions and plasma particles are treated by the PIC method. The effects of the beam density on the wakefield and stopping power are then obtained and discussed. It is found that as the beam densities increase, the oscillation wakefield induced by the beam become stronger. Besides, the first oscillation wakefield behind the bunch is particularly stronger than others. Moreover, it is found that the stationary stopping power increases linearly with the increase of the beam density in the linear/semilinear region.

The effects of a radiation field (RF) on the interaction process of a relativistic electron beam (REB) with an electron plasma are investigated. The stopping power of the test electron averaged with a period of the RF has been calculated assuming an underdense plasma, ω0 > ωp, where ω0 is the frequency of the RF and ωp is the plasma frequency. In order to highlight the effect of the radiation field we present a comparison of our analytical and numerical results obtained for nonzero RF with those for vanishing RF. In particular, it has been shown that the weak RF increases the mean energy loss for small angles between the velocity of the REB and the direction of polarization of the RF while decreasing it at large angles. Furthermore, the relative deviation of the energy loss from the field-free value is strongly reduced with increasing the beam energy. Special case of the parallel orientation of the polarization of the RF with respect to the beam velocity has been also considered. At high-intensities of the RF two extreme regimes have been distinguished when the excited harmonics cancel effectively each other reducing strongly the energy loss or increasing it due to the constructive interference. Moreover, it has been demonstrated that the energy loss of the ultrarelativistic electron beam increases systematically with the intensity of the RF exceeding essentially the field-free value.

The electron emission yield γ induced by Ne2+ and O2+ impacting on a clean tungsten surface has been measured. The range of projectile energy is from 3 keV/u to 14 keV/u. The total electron yield gradually increases with the projectile velocity. It is found simultaneously that the total electron yield for O2+ is larger than the total electron yield for Ne2+, which is opposite to the results for higher projectile velocity. After considering the contribution from recoiling atoms to the energy distribution and electron emission yield, we find that recoiling atoms are of crucial importance in electron emission in our energy range. Thus, the unexpected results in our experiment can be explained successfully.

The inelastic interaction between heavy ions and an electron plasma in the presence of an intense radiation field (RF) is investigated. The stopping power of the test ion averaged with a period of the RF has been calculated assuming that ω0 > ωp, where ω0 is the frequency of the RF and ωp is the plasma frequency. In order to highlight the effect of the radiation field we present a comparison of our analytical and numerical results obtained for nonzero RF with those for vanishing RF. It has been shown that the RF may strongly reduce the mean energy loss for slow ions while increasing it at high–velocities. Moreover, it has been shown, that acceleration of the projectile ion due to the RF is expected at high–velocities and in the high–intensity limit of the RF, when the quiver velocity of the plasma electrons exceeds the ion velocity.

In contrast to the usual laser fusion scheme with spherical irradiation and very high compression and ignition of fuel, the alternative scheme with side-on ignition of uncompressed solid density of fuel (Chu) may lead to a solution by using the now available picosecond laser pulses with higher than petawatt power. A necessary condition is to use clean laser pulses with better than 108 contrast ratio for suppression of relativistic self-focusing. When updating the analysis of Chu for fusion of deuterium-tritium and proton-11B, one problem is that the correct use of the stopping power of the alpha particles had to be solved. Discrepancies are evaluated in view of the stopping power at the low temperature range of the plasmas where the change of the emitted bremsstrahlung is involved.

The theoretical description of the energy loss of heavy ions in fully ionized matter is considered, where we focus on the many–body and plasma physics aspects of the stopping of point like projectiles with a fixed charge by free electrons, disregarding the atomic physics of the projectile and the target ions. This starts by identifying different coupling regimes for a heavy ion which passes through an electron plasma, and continues with a discussion of the available and appropriate analytical and numerical treatments of the energy loss and their applicability in these various regimes. Special attention is given to a nonlinear coupling regime with significant strong coupling effects on the projectile-target energy transfer where standard perturbative approaches cease to be valid. More advanced theoretical treatments, which are required for this regime, are presented, discussed and evaluated by comparison with simulation results.

The interaction process between fast heavy ions and dense plasma was experimentally investigated. We injected 4.3-MeV/u or 6.0-MeV/u iron ions into a z-pinch-discharge helium plasma and measured the energy loss of the ions by the time of flight method. The energy loss of 4.3-MeV/u ions fairly agreed with theoretical prediction when the electron density of the target was on the order of 1018 cm−3. With increasing electron density beyond 1019 cm−3, the difference between the experiment and the theory became remarkable; the experimental energy loss was 15% larger than the theoretical value at the peak density. For 6.0-MeV/u ions, the deviation from the theory appeared even at densities below 1019 cm−3. These discrepancies indicated that density effects such as ladderlike ionization caused the enhancement of the projectile mean charge in the target.

Quasi-linear analysis demonstrates that intense and nonrelativistic proton beams do not lose collectively their kinetic energy through transverse Weibel electromagnetic instabilities when interacting with supercompressed plasmas of inertial confinement interest.

The article presents the results of the experimental research on precision measurement of total stopping range and energy deposition function of intermediate and heavy ion beams in cold solid matter. The “thick target” method proves to be appropriate for this purpose. Two types of detectors were developed which provide an error of the total stopping range measurement of less than 3% and of the beam energy deposition function of about 7%. The experiments with 58Ni+26, 197Au+65, and 238U+72 ion beams in the energy range 100–300 MeV/u were performed on SIS-18 (Gesellschaft für Schwerionenforschung, Darmstadt) in 1999–2001. The measured data on the total stopping ranges for the above ion species in bulk and foiled Al and Cu targets are presented. The investigation showed that there is a noticeable discrepancy between the measured stopping ranges and the theoretically predicted ones. Also, it was shown that realistic ion energy deposition depends on the type of target (bulk or foiled). Further investigation is necessary to clarify the latter.

In this article, we analyze the sensitivity of the charge and energy distribution of a swift heavy ion beam interacting with a dense plasma on the thermodynamic and dynamic properties of the target. We study more particularly partially ionized carbon targets in which both the bound and the free electrons yield a significant contribution to the stopping. The emphasis is put on direct and indirect correlation between charge transfer and stopping. We show that nonlinearities, appearing in the interaction process for heavy ions, increase the dependency of the stopping on the plasma properties, indicating that diagnostics based on the analysis of the beam ions can provide valuable information on the target properties.

A model for the stopping power for strong beam–plasma coupling is presented. The model calculates the stopping power through a T-matrix approach which correctly describes close binary collisions. A velocity-dependent screening length is used in the beam particle–plasma electron interaction to include dynamic screening effects. The model has the correct limiting behavior for low and high beam particle velocities and agrees well with simulation data up to very high coupling strengths. Compared to other theories, which include strong correlations and/or dynamic screening only approximately, a smaller energy loss has been found; this leads to a considerably longer stopping range.

The X-ray spectral distribution of swift heavy Ti and Ni ions (11 MeV/u) observed inside aerogels (ρ = 0.1 g/cm3) and dense solids (quartz, ρ = 2.23 g/cm3) indicates a strong presence of simultaneous 3–5 charge states with one K-hole. We show that the theoretical analysis can be split into two tasks: first, the treatment of complex autoionizing states together with the originating spectral distribution, and, second, a charge-state distribution model. Involving the generalized line profile function theory, we discuss attempts to couple charge-state distributions.