The hard X-ray (>30 keV) continuum from the interaction of a Ti:sapphire/KrF intense femtosecond UV laser (50 mJ, 440 fs, 10 Hz at 248 nm) with a solid has been measured; the intensity on the target is up to 1017 W/cm2. The X-ray with energy of 200 keV has been observed; the temperature of the hot electron from fitting the spectrum utilizing Maxwellian distribution is 67 keV. This is the first measurement of hard X-rays from femtosecond KrF laser–solid interaction.

Recent measurements of the absorption coefficients of L transitions in iron and nickel hot plasmas are reported following a brief review of the published experiments on opacities and absorption coefficients which have been performed until now in laser-heated cavities and Z-pinches. Emphasis is put on the impact of these measurements in astrophysics.

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.

While beam loss issues have hardly been considered in detail for heavy ion fusion scenarios, recent heavy ion machine developments in different labs (European Organization for Nuclear Research(CERN), Gesellschaft für Schwerionenforschung (GSI), Institute for Theoretical and Experimental Physics (ITEP), Relativistic Heavy-Ion Collider (RHIC)) have shown the great importance of beam current limitations due to ion losses. Two aspects of beam losses in heavy ion accelerators are theoretically considered: (1) secondary neutron production due to lost ions, and (2) vacuum pressure instability due to charge exchange losses. Calculations are compared and found to be in good agreement with measured data. The application to a Heavy-Ion Driven Inertial Fusion (HIDIF) scenario is discussed.

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 present measurements of the components' surface resistance to laser-induced damage has been completed to facilitate development and construction of the “Luch” laser system, a four-channel Nd-phosphate glass laser with a full output energy of E = 14–16 kJ. The study describes a method that, with a series of experimental data obtained from a single sample, allows us not only to estimate the threshold fluences, but to take into account the statistical nature of the surface damage. In a number of experimental situations this method makes it possible to estimate damaging fluences even from the result of a single exposure of the studied surface. Estimated threshold fluences for various optical elements are presented: K8 glass, experimental phosphate laser glass KGSS-0180, high-reflecting and antireflecting thin-film coating of elements. The 1.054-μm radiation pulse with half-height duration of 4 ns and the irradiation spot of ∼4 mm in diameter were used in the experiment.

Due to an error, the published version of the paper differed from the final version submitted by the authors. The section starting at page 271 with “The beams are well collimated …” and finishing at the end of the page, and the caption for figure 4 were to be replaced with an updated version, submitted on 20 May 2002, which follows underneath.

Chromatin is the complex of deoxyribonucleic acid (DNA) with proteins that exists in eukaryotic cell nuclei. Chromatin was extracted from livers of Wistar rats and subjected to a 248-nm excimer laser radiation, in doses of 0.5–3 MJ/m2. An UV excimer laser Iofan 1701, with 40-mJ dose/pulse and frequency of 30 Hz was used. The radiolysis of chromatin was analyzed by (1) 1H-NMR spectroscopy, (2) steady-state fluorescence, (3) time-resolved fluorescence, and (4) fluorescence resonance energy transfer (FRET) methods. The laser action on chromatin determines bigger values of the transverse relaxation time (T2), which indicates less bound water in the chromatin structure, therefore a more injured one. The chromatin intrinsic fluorescence decreases on laser action, proving the destruction of the chromatin protein structure. By the time-resolved fluorescence we established that the relative contribution of the excited state lifetime of bound ethidium bromide to chromatin DNA diminishes with the laser dose. This denotes single- and double-strand breaks produced in DNA structure. By the FRET method, the energy transfer efficiency and the distance between dansyl chloride and acridine orange coupled at chromatin were determined. The distance increases with laser action. The determination of the chromatin structure modification in an excimer laser field can be of real interest in medical applications.

In this work, a new analytical potential for studying ions in excited configurations is presented, which is built up from a parametric potential for ions in a ground state. It is used to calculate atomic magnitudes of special importance in plasmas such as total energies, energy levels, and transition energies, for ions in excited configurations. The results are successfully compared with those obtained with both self-consistent or analytical models.

The coefficients Ai, that enter the fit formula for the stopping power (6), are given incorrectly in table 1. The table gives expressions for the quantities Ai2, rather than the coefficients Ai as printed. Therefore, the square root of the given expressions should be computed to obtain Ai. The given accuracy of the fit is reported correctly since it was obtained using the correct coefficients.

The charge-state distribution and the energy loss of oxygen ions in a laser-produced hydrogen plasma have been investigated experimentally. The plasma target had a maximum electron density of 5 × 1018 cm−3 and a maximum electron temperature of 13 eV. The mean charge state of the oxygen ions in the hydrogen plasma was measured to be 5.1, which was considerably higher than that in hydrogen gas. The energy loss of oxygen ions in the plasma of a density less than 1 × 1018 cm−3 in the plasma showed a large enhancement compared with that in hydrogen gas. However, the energy loss in the plasma of a density above 1 × 1018 cm−3 showed no enhancement.

The paper discusses recent advances in the use of foams in laser–plasma experiments, concerning in particular: (1) the use of foam in order to get an efficient smoothing of laser energy deposition, (2) the problem of hydrodynamics of layered foam-payload targets, (3) the use of foam for shock pressure amplification in equation-of-state experiments, (4) the study of the equation of state of foams in the Megabar regime, and (5) the use of foams for astrophysics relevant experiments, here in particular shock acceleration experiments.

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.

New results concerning the process of dynamic fracture of materials (spallation) by laser-induced shock waves are presented. The Nd-glass laser installations SIRIUS and KAMERTON were used for generation of shock waves with pressure up to 1 Mbar in plane Al alloy targets. The wavelengths of laser radiation were 1.06 and 0.53 μm, the target thickness was changed from 180 to 460 μm, and the laser radiation was focused in a spot with a 1-mm diameter on the surface of AMg6M aluminum alloy targets. Experimental results were compared to predictions of a numerical code which employed a real semiempirical wide-range equation of state. Strain rates in experiments were changed from 106 to 5 × 107 s−1. Two regimes of spallation were evidenced: the already known dynamic regime and a new quasi-stationary regime. An ultimate dynamic strength of 80 kbar was measured. Finally, experiments on targets with artificial spall layers were performed showing material hardening due to shock-wave compression.

In this work, the Saha equation is solved using atomic data provided by means of a new relativistic-screened hydrogenic model based on analytical potentials to calculate the ionization state and ion abundance for LTE iron plasmas. The plasma effects on the atomic structure are taken into account by including the classical continuum lowering correction of Stewart and Pyatt. For high density, the Saha equation is modified to consider the degeneration of free electrons using the Fermi–Dirac statistics instead of the Maxwellian distribution commonly used. The results are compared with more sophisticated self-consistent codes.

The paper reviews and analyses the experiments devoted to the propagation in dense matter of fast electrons produced in the interaction of short-pulse ultra-high-intensity laser pulses with solid density targets.

At the Gesellschaft für Schwerionenforschung (GSI, Darmstadt) intense beams of energetic heavy ions have been used to generate high-energy-density (HED) state in matter by impact on solid targets. Recently, we have developed a new method by which we use the same heavy ion beam that heats the target to provide information about the physical state of the interior of the target (Varentsov et al., 2001). This is accomplished by measuring the energy loss dynamics (ELD) of the beam emerging from the back surface of the target. For this purpose, a new time-resolving energy loss spectrometer (scintillating Bragg-peak (SBP) spectrometer) has been developed. In our experiments we have measured energy loss dynamics of intense beams of 238U, 86Kr, 40Ar, and 18O ions during the interaction with solid rare-gas targets, such as solid Ne and solid Xe. We observed continuous reduction in the energy loss during the interaction time due to rapid hydrodynamic response of the ion-beam-heated target matter. These are the first measurements of this kind. Two-dimensional hydrodynamic simulations were carried out using the beam and target parameters of the experiments. The conducted research has established that the ELD measurement technique is an excellent diagnostic method for HED matter. It specifically allows for direct and quantitative comparison with the results of hydrodynamic simulations, providing experimental data for verification of computer codes and underlying theoretical models. The ELD measurements will be used as a standard diagnostics in the future experiments on investigation of the HED matter induced by intense heavy ion beams, such as the HI-HEX (Heavy Ion Heating and EXpansion) EOS studies (Hoffmann et al., 2002).

In this work, we study the laser propagation in a thermonuclear plasma corresponding to implosion of deuterium-tritium pellets in inertial confinement fusion, by injecting energy provided by high-power laser devices into a quiescent plasma and generating solitons. Having in mind that the electric field inside of plasma can be studied by means of a particular non-linear Schrödinger equation, we solve this equation as an inverse problem, using the Inverse Scattering Transform method, that is a 2 × 2 eigenvalue problem, known as the AKNS scheme, developed by Ablovitz, Kamp, Newell, and Shabat. We obtain the pseudopotentials q and r if we suppose that the eigenvalue is invariant in time, and is representative of a wave eigenvector, obtaining a solution that has a structure of the soliton type. In the process, one change of variable for space and another for time are applied, and the relation between the pseudopotentials is given by r = −q*. Discretization of the non-linear Schrödinger equation, solved by inverse scattering transform are given by Ablovitz et al. (1999). These solitons are generated near the critical layer where w0 ≅ wp, w0 being the laser frequency and wp the plasma frequency, exhibit a change in electronic density profile and are caused by the ponderomotive force of laser radiation.

By analytical modeling and numerical simulation, we show that surface modes in moderately overdense plasmas may be excited parametrically by an intense, ultrashort laser pulse. This process has a feedback effect on fast electron generation and may seed a fast distortion of plasma “moving mirrors.”

In heavy ion fusion, the compression of the DT pellet requires high intensity beams of ions in the gigaelectron volt energy range. Charge-changing collisions due to intrabeam scattering can have a high impact on the design of adequate accelerator and storage rings. Not only do intensity losses have to be taken into account, but also the deposition of energy on the beam lines after bending magnets, for example, may be nonnegligible. The center-of-mass energy for these intrabeam collisions is typically in the kiloelectron volt range for beam energies in the order of several gigaelectron volts. In this article, we present experimental cross sections for charge transfer and ionization in homonuclear collisions of Ar4+, Kr4+, and Xe4+, and for charge transfer only in homonuclear collisions of Pb4+ and Bi4+. Using a hypothetical 100-Tm synchrotron as an example, expected particle losses are calculated based on the experimental data. The results are compared with expectations for singly charged Bi+ ions, which are usually considered for heavy ion fusion.