The relaxation of two-temperature electron–ion systems is investigated. We apply a quantum kinetic approach which is suitable to treat strong electron–ion coupling and avoids any ad hoc cut-off procedures. A comparison with the usual Landau–Spitzer formula gives good agreement for Coulomb logarithms larger than three, whereas larger relaxation rates were found for strongly coupled plasmas. It is shown that the Landau–Spitzer theory can be greatly improved considering hyperbolic orbits. Numerical results for the energy transfer rates and the temporal behavior of the electron temperature are shown.

As an important part of my duty and as a first step as incoming editor to this journal it is a great pleasure for me to thank Professor George H. Miley for his work that he did for over a decade as the editor-in-chief of Laser and Particle Beams. During a period of over 20 years, the field, which this journal has set out to address, has experienced enormous progress. George H. Miley steered the journal safely through uncharted waters and always found a way to keep the delicate balance between the needs of readers, authors, and the publisher as well. The journal is now regarded to be highly prestigious and it is listed among the top ranking scientific journals with peer review systems. When we compare this journal to others, we have to keep in mind that it is not made by professional journalists but rather by fellow scientists for scientists. During all these years George Miley managed to have this journal serve the needs of the scientific community and he was very successful in this difficult enterprise. Thank you George!

This issue of Laser and Particle Beams contains the papers submitted for publication by participants of the 14th International Heavy Ion Inertial Fusion (HIF) Symposium held in Moscow, May 26–31, 2002. This conference was organized by State Research Center of Russian Federation, Institute for Theoretical and Experimental Physics, Moscow, under the auspices of the International Atomic Energy Agency, Beam Plasma and Inertial Fusion Section of the European Physical Society, and Accelerator Council of Russian Academy of Science. The symposium was supported by the Ministry of Atomic Energy of Russian Federation, Russian Academy of Science, Russian Foundation for Basic Research, International Science, and Technology Center, and by GSI Darmstadt.

This issue of Laser and Particle Beams contains 25 papers that were presented at the conference on “Matter in Super-Intense Laser Fields: Short Pulse, Superstrong Laser-Plasma Interactions,” held in S. Feliu de Guixols, Spain, from 29 September to 4 October 2001. Almost 100 scientists and young researchers (Ph.D. students and Post Docs) took part in this successful event, despite the terrible terrorist acts of September 11, 2001 in New York, which prevented many speakers from taking part, especially those coming from the United States.

New experimental results of investigations of the interactions of an intense 4.3-GeV electron beam with an aligned single crystal are given in the case when the electrons travel close to the crystalline planes (110). The growth of low energy radiation yields with the intensity of the electron beam and the peculiar properties of the produced γ-quanta at their passage through a small collimator aperture were observed. Large angular asymmetry at the scattering of low energy γ-quanta, which is evidence of high polarization of the radiation, was also detected. These unexpected phenomena may be stimulated by strong correlations of atomic excitations in crystals. The obtained results will be of use for understanding of the properties of both the excited crystalline medium and the mechanism of intense radiation under these conditions and also for practical applications of the radiation.

Significant experimental and theoretical progress has been made in the U.S. heavy ion fusion program on high-current sources, transport, and focusing. Currents over 200 mA have been transported through a matching section and 10 half-lattice periods with electric quadrupoles. An experiment shows control of high-beam current with an aperture, while avoiding secondary electrons. New theory and simulations of the neutralization of intense beam space charge with plasma in various focusing chamber configurations predict that near-emittance-limited beam focal spot sizes can be obtained even with beam perveance (ratio of beam space potential to ion energy) >10× higher than in earlier HIF focusing experiments. Progress in a new focusing experiment with plasma neutralization up to 10−3 perveance, and designs for a next-step experiment to study beam brightness evolution from source to target are described.

This issue of Laser and Particle Beams Journal contains the papers submitted for publication by participants of the 26th European Conference on Laser Interaction with Matter—this Conference (also known by its acronym ECLIM 2000) was organized jointly by the Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University in Prague, the Institute of Physics of the Academy of Sciences of the Czech Republic, and supported by the International Society for Optical Engineering, this conference was held in Prague from June 12–16, 2000.

Results are presented for a theoretical model, known as the ion model (IM), recently elaborated to calculate the radiative opacity of a hot dense plasma. The density functional theory is used to obtain the general set of self-consistent field equations that describe the state of the whole ensemble of plasma atoms and ions. Theoretical features of the Hartree–Fock–Slater model, the detail configuration account, and the IM are considered. The IM is used for optimal selections of compound chemical compositions for laser and heavy ion target designs.

One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 MeV/amu with charge state 1 currently do not exist. Hence, the stripping cross sections used to model the performance of heavy ion fusion driver beams have, up to now, been based on theoretical calculations. We have investigated experimentally the stripping of 3.4 MeV/amu Kr+7 and Xe+11 in N2; 10.2 MeV/amu Ar+6 in He, N2, Ar, and Xe; 19 MeV/amu Ar+8 in He, N2, Ar, and Xe; 30 MeV He+1 in He, N2, Ar, and Xe; and 38 MeV/amu N+6 in He, N2, Ar, and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

Inertial confinement fusion (ICF) has developed remarkably in the last 30 years. In the 21st century, we can expect fusion energy for civilian use. After the cold war era, the value of ICF has shifted from defense demands to peaceful applications. The megajoule laser systems are under construction expecting the development of spark ignition. However there are many problems to solve in science and technology. One alternative way is to use a petawatt short-pulse laser aiming for fast ignition. On the way to the final goal, we would like to contribute for various applications of high power lasers such as laboratory astrophysics, X-ray lasers, laser-induced lightning as well as laser processing.

This article presents analytical and simulation studies of intense heavy ion beam propagation, including the injection, acceleration, transport and compression phases, and beam transport and focusing in background plasma in the target chamber. Analytical theory and simulations that support the High Current Experiment (HCX), the Neutralized Transport Experiment (NTX), and the advanced injector development program, are being used to provide a basic understanding of the nonlinear beam dynamics and collective processes, and to develop design concepts for the next-step Integrated Beam Experiment (IBX), an Integrated Research Experiment (IRE), and a heavy ion fusion driver. Three-dimensional nonlinear perturbative simulations have been applied to collective instabilities driven by beam temperature anisotropy, and to two-stream interactions between the beam ions and any unwanted background electrons; three-dimensional particle-in-cell simulations of the 2-MV electrostatic quadrupole (ESQ) injector have clarified the influence of pulse rise time; analytical studies and simulations of the drift compression process have been carried out; syntheses of a four-dimensional particle distribution function from phase-space projections have been developed; and studies of the generation and trapping of stray electrons in the beam self-fields have been performed. Particle-in-cell simulations, involving preformed plasma, are being used to study the influence of charge and current neutralization on the focusing of the ion beam in NTX and in a fusion chamber.

We have studied the interaction of soft X-ray thermal radiation with foam-layered metal targets. The X-radiation was produced by focusing a high energy laser inside a small size hohlraum. An increment in shock pressure was observed with the foam layer as compared to bare metal targets.

Two experiments have been performed to investigate heating by high-intensity laser-generated electrons, in the context of studies of the fast ignitor approach to inertial confinement fusion (ICF). A new spectrometer and layered targets have been used to detect Kα emission from aluminum heated by a fast electron beam. Results show that a temperature of about 40 eV is reached in solid density aluminum up to a depth of about 100 μm.

Correlations of Doppler shifted line shapes with time-of-flight spectra of fast ions has been established for nanosecond-laser pulses. Fast ion energies of different velocity groups have been established in the large interval of Iλ2 = 4 × 1012–5 × 1016 W/cm2 μm2. The obtained scaling relations differ markedly from those reported by Gitomer et al. (1996).

The construction of the Terawatt Accumulator (TWAC) facility is nearly completed at the ITEP in Moscow. All the major milestones have been successfully passed with a beam of carbon ions, except for the final result (the high power beam accumulation), which is on the way. The beam of C4+ ions delivered by the laser ion source is accelerated up to the energy of 300 MeV/amu by two steps—in the linear injector I3 and in the booster synchrotron UK. The accelerated beam is extracted from the UK ring and transferred to the U10 accumulator ring. Non-Liouvillian stripping technique (C4+ ⇒ C6+) is applied for stacking of C6+ batches into the accumulator ring U10. First experiments with extracted beam of ions have started in 2002. Status of the TWAC components, current results of activities aiming at mastering the ion beam stacking technique, and outlook for the TWAC advance are presented.

In this report, we discuss the physical concept and the results of mathematical modeling of free-standing target (FST) layering for inertial confinement fusion (ICF), including the detailed descriptions of the heat transfer and layer symmetrization mechanisms.

The aim of the presented experiments is to study the transport of a heavy ion beam in a high-current plasma channel. The discharge is initiated in NH3 gas at pressures between 2 and 20 mbar by a line-tuned CO2 laser. A stable discharge over the entire electrode gap (0.5 m) was achieved for currents up to 60 kA. Concerning the ion beam transport, the magnetic field distribution inside the plasma channel has to be known. The ion-optical properties of the plasma channel have been investigated using different species of heavy ions (C, Ni, Au, U) with 11.4 MeV/u during six runs at the Gesellschaft für Schwerionenforschungs-UNILAC linear accelerator. The high magnetic field allowed the accomplishment of one complete betatron oscillation along the discharge channel. The results obtained up to now are very promising and suggest that, by scaling the discharge gap to longer distances, the beam transport over several meters is possible with negligible losses.

Obtaining an X-ray laser emission from plasmas, created and driven by an intense IR laser, has been pursued at the Laboratoire de Spectroscopie Atomique et Ionique (LSAI) for several years. At present, we operate various types of X-ray lasers driven by IR laser pulses of different durations (600 ps, 100 ps, and 600 ps/1 ps). A review of different techniques used at the LSAI to produce a strongly amplified emission using the collisional excitation pumping is presented. In the second part of this paper, to illustrate the potential of the X-ray lasers for applications, we present the main results obtained with an X-ray laser emitting at 21.2 nm in a study of surface defects of a niobium cathode, induced by strong electrical fields. We also describe a novel imaging interferometry device using an X-ray laser as a source and designed as a tool for high-resolution diagnostic of dense plasmas.

A treatment is given of harmonics generation resulting from nonlinear inverse bremsstrahlung in a plasma with an anisotropic bi-Maxwellian electron velocity distribution function. A complete characterization of the process is reported. In particular, analytically and numerically we established how the efficiency of the odd harmonics generation and their polarization depend on such process parameters as: (1) the degree of effective temperature anisotropy, (2) the frequency and the intensity of the fundamental wave, and (3) the angle between the fundamental wave field direction and the symmetry axis of the electron distribution function.

This paper presents two-dimensional numerical simulations of heating of matter with intense heavy ion beams. It has been shown that it is very advantageous to irradiate the target with two different beams simultaneously, a main high intensity bunched beam of a heavy element like uranium and an unbunched low intensity beam of a lighter element like argon. The main beam is used to heat the target while the second beam is used as a diagnostic tool.

Influence of the shape of the focal spot on compression and heating of matter has also been studied using an elliptic focal spot with an ellipticity of 1.5 (semimajor axis is along y-axis and is 1.5 times the semiminor axis which is along x-axis). It has been found that the temporal behavior of the development of density, pressure, and temperature profiles along different directions is quite different, which is not the case with a circular focal spot.