It is shown that a powerful laser beam is capable of the ponderomotive confinement of plasma with electron density exceeding the critical density for the radiation under review. The theory describing force and heat balances of the plasma together with the propagation of the laser radiation is developed. The laws of the dense plasma scaling for controlled thermonuclear fusion (CTF) and other applications are formulated.

The Precision Phebus program, started in 1993, emphasizes a series of laser and target experiment objectives on the two-beam Phebus Nd-phosphate glass laser. Recently, three major objectives that are also very important issues for megajoule-class lasers have been met: First, the balance of the incident beam-to-beam 3ω power is shown to be in the range from 5 to 12% for 3-ns, 3ω-shaped pulses of reproducible high-energy shots; second, the smoothing uniformity of the laser energy deposited on the target, that is, the contrast of the spatial beam modulations, can be kept lower than 5%; and, finally, the tight control of the beam targeting leads to a pointing precision of less than 10 μrd on the target at the target chamber center (TCC) and of 80 μrd on X-ray sources located up to 3 cm from the TCC to improve the space- and time-resolved X-ray shadowgraphy techniques performed for target physics experiments such as implosion and hydrodynamical instability studies.

Free-electron lasers exploiting media with periodically modulated refractive indices are studied. The regime of large modulation is considered, and the conditions of its realization are discussed. Two types of media with periodically modulated refractive indices are analyzed: a gas-plasma medium with a periodically varying degree of ionization and a superlattice-like medium. The gain, saturation field, and efficiency of these free-electron lasers are found. For any given frequency, the gain is optimized with respect to the choice of electron energy, direction of motion, and other parameters. Its relationship with other types of free-electron lasers (e.g., the Cherenkov laser) is discussed.

The generation of poloidal magnetic field in an inhomogeneous cold, collisionless plasma by an elliptically polarized Gaussian laser beam is discussed. A field in the range of megagauss is induced by the laser inhomogeneity effect even for a normal incident beam. This field scales as I0 λ, where I0 and λ are the intensity and wavelength of the laser beam, respectively, and is independent of the density profile structure. The small angular correction factor due to focal spot asymmetry scales as ∼I0λ3 and may be significant for a small-sized plasma with a steep density profile. The limitation of our model is discussed, with possible implications.

Intense electron beams are known to produce surface plasmas when they strike typical target materials. The beam space charge then draws an ion current that can substantially affect the beam dynamics. We consider these effects for two intense-beam sources: (1) a needle-tip cathode immersed in a strong magnetic field, and (2) an induction accelerator-produced beam that is focused onto a field-free target. For the first case, the dominant effect is an electrostatic dipole instability between the beam and the ions. A sufficiently large magnetic field can keep the oscillation amplitude to a low level. For the second case, the dominant effect is that the focal length changes in time. For the “worst case” of space-charge-limited proton emission, the predicted effect is severe. The actual abundance and charge state of the target-plasma ions will need to be measured or inferred from planned experiments. Mitigation schemes also are discussed briefly.

Basic relations are presented to calculate isotope enrichment and depletion factors in a supercooled flow of gaseous QF6 molecules mixed with Ar (or another carrier gas) that is coaxially or cross-wise illuminated with a laser beam. Isotope-selective laser excitation of iQF6 molecules retards their condensation on walls and during cluster growth. This yields an isotope-enriched gas and isotope-depleted wall deposits under subsonic flow conditions and coaxial laser irradiation. Similarly, enriched QF6 gas and depleted particle clusters are formed in supercooled supersonic expansion flows that are coaxially or cross-wise irradiated. Measured isotope changes for 32SF6/34SF6 and 235UF6/238UF6 are shown to be in agreement with calculated values.

The expansion of a laser-produced plasma is studied using two computational methods and compared to experiments. The simulations and experiments were performed using a l-μxm, 600-mJ, 6-ns laser pulse. It was found that there was good agreement between the ID Lagrangian code, the snow plow model, and the experiments for our conditions.

The main goals of this review article are to show, on the basis of the results accumulated in this field, achievements in simulating the processes in nuclear pumped laser (NPL) active media by experiments on e-beam pumping, and to give a number of characteristic experimental examples, when this simulation has improved understanding of the inversion population processes in NPL active media (Cd+, Xe-lasers) or generated interest in experiments with fission fragments excitation (Ne-laser). In the case of the population of laser operation levels in non-equilibrium recombinating plasma, one can say with sufficient accuracy that the inversion population mechanism is identical for both excitation types.

Recent progress in laser-plasma accelerators has matured a concept of particle acceleration as a possible next-generation particle accelerator promising ultrahigh accelerating gradients in a compact size. Four major concepts of laser-plasma accelerators—the plasma beat wave accelerator, the laser wakefield accelerator, the self-modulated laser wakefield accelerator, and the plasma wakefield accelerator—are reviewed on accelerator physics issues and experiments demonstrating the basic mechanisms of their concepts. As a perspective to the future practical application, a design of 5-TeV linear colliders based on the laser wakefield accelerator is discussed.

An investigation of second harmonic (SH) and X-ray emissions from Al plasmas produced by 3-ns, 1.064-μm laser pulses at 1014 W/cm2 is reported. The SH and X-ray yields are strongly correlated as a function of the target position with respect to the laser beam focus. The SH originates from the underdense coronal plasma and has a filamentary source, while the X-ray source is uniform. The results suggest that, although the X-ray emission is significantly enhanced by the filamentation of the laser light in the corona, there is a smoothing effect in the energy transport process toward the overdense region.