Self-focusing of laser beams in plasma is studied analytically using the thermal (collision produced) and ponderomotive (nonlinear force produced) effects based on the model of Zakharov with solutions of the nonlinear Schrödinger equation. A basic difference appears if the electric field amplitude E is less than the threshold Eth (at which the electrodynamic energy density is equal to the gasdynamic pressure) from the contrary case, E > Eth.The length of the filamentation process is evaluated and results in large values for E below Eth.

Ponderomotive force initiated laser self focusing can be enhanced by relativistic electron motion in a laser plasma. We derive the nonlinear refractive index due to relativistic effects and find that relativistic self focusing becomes important for a 0·25 μm laser when the laser intensity exceeds 5 × 1018 W/cm2.

This paper discusses the principles of reduction of quantum noise in optical radiation. The dynamics of photon number fluctuations in direct and cascade two-photon processes is investigated. The paper considers the cases of absorption and emission for the fields originally prepared in coherent and thermal states. It is shown that photon antibunching and bunching should occur for the passed radiation. The photon antibunching effect is only in definite time intervals of field interaction with resonance absorbing or emitting systems.

The possible cases of accumulation of photon antibunching effects are considered.

We investigate the Fokker–Planck Equation (FPE) in which we retain electron–ion and electron–electron collision terms, as well as the inverse-bremsstrahlung absorption term. We exhibit asymptotic solutions, which are then used in a linear perturbation theory ‘à la Spitzer’, to calculate local transport coefficients. Their values can differ drastically from classical results, which in turn alters hydrocode simulations.

The explosive growth of electron temperature, produced by microwave heating of a collisional magnetoplasma in the vicinity of Langmuir resonance, is illustrated. This explosion is localized near by the irradiated surface of plasma volume. Such effect is stipulated by an external magnetic field, herein this field may be weak enough.

The phase diagram of high density (1023 ˜ 1027/cm3) deuterium is obtained by calculation. The values of specific heat, electrical resistivity and thermal conductivity in the metallic state are estimated over a wide range of temperature (10−2 ˜ 104 eV). The temperature dependences of these properties are shown in figures with the density. When T ≤ Tf (Tf: the Fermi temperature of electrons), the behavior is very similar to those of normal metals. At high temperatures where T ≥ Tf, the behavior is similar to that of completely ionized classical plasma.

This fundamental data for deuterium will help us understand the properties of fuel in inertial-confinement fusion and to solve the fluid equations for efficient compression of fuel pellets.

A linear parametric theory of laser light instabilities including decay, stimulated Raman and Brillouin scattering, etc. is currently well developed. However, attention is drawn to a novel laser light instability against parametric excitation of magneto-static fluctuations. In a collisionless plasma regime, magneto-static fields are driven by the ponderomotive electron magnetization current. Generally, two types of magneto-static instabilities exist: magneto-modulational instability and stimulated magneto-static scattering instability. Growth rates are calculated which indicate the possible importance for high laser intensity driven hot plasma regimes.

The research of particle beam fusion and its related problems at The Institute of Atomic Energy in Beijing is evolving along the following five directions: 1. Pulsed power technology. An 80 GW intense electron beam accelerator has been built. Switch research is ongoing. 2. Diode research. The experimental research and theoretical simulation of electron pinch in the diode have been carried out. The pinch process has been investigated by measuring the area collapsing velocity of the pinching electron ring on the anode surface. Expanding velocities of the cathode and anode plasmas have been observed. The diode with large area cathode of 38 × 5 cm2 can produce a 46 kA electron beam current with a beam cross-section of 36 × 4 cm2 and good uniformity for pumping of a KrF laser. 3. Energy deposition of the electron beam on the targets has been studied by means of measurements of the intensity of soft X-rays, the energy spectrum of blow-off ions, the visible light spectra and the rear surface velocity of the target. These experiments show that the results are in agreement with the classical interaction mechanism for high Z targets, but it is several times higher than the classical result for low Z targets. 4. Electron beam propagation in neutral gases with various pressures space-and current-neutralization processes have been investigated. 5. The production of a KrF laser pumped by an electron beam. A laser beam with an energy of 13 J and pulse duration of 70 ns has been obtained.

1½ D computer simulations have been performed to illustrate the influence of ion dynamics on stimulated Raman scattering in laser irradiated plasmas. A flat density profile has been used. Backward and forward scatter and heated electron distribution have been studied as a function of ion mass and ion temperature. The results show clearly that the lighter the ions, the more inhibited the Raman scatter and associated fast electron production. Futhermore, when ions are cold enough to allow Brillouin scattering release, Raman scatter, as well as associated suprathermal electrons is even more reduced. These observations evidence the complex non-linear coupling of the electron plasma waves driven by the Raman instability and the ion fluctuations which can exist in the plasma.

Multiple-pass amplifiers were configured from Nd:glass rods using polarization and angular coupling techniques. Very high gain (>600) single beam triple-pass booster stages and high gain (30 or 15) single or double-beam double-pass amplifiers were combined to construct a very cost effective high-power (50 GW) pulsed laser system. These techniques were also effectively applied to smaller compact high repetition-rate systems.

Sensitivity analysis is a powerful first-order mathematical technique that identifies the major reactions, the effects of errors in rate constants, pressure effects, and temperature effects in a plasma chemistry type model. Several methods of sensitivity analysis have been discussed in the literature. This paper describes the successful implementation of the state transition matrix method to the sensitivity analysis of a plasma chemistry model using both e-beams and ions for excitation. The ion excited plasma study is important to the field of nuclear-pumped lasers. This model examines 8 species and 37 reactions.

Numerical simulations of proton stopping lengths in aluminum slab plasmas have been done using a modified version of the MEDUSA-KA code and compared to other published computations. Simulations have been performed for proton beam parameters consistent with future experiments on the KALIF light ion accelerator at KfK including carbon contamination of the beam. These simulations show that proton range shortening should be evident in KALIF experiments and that the carbon contamination must be removed to allow interpretation of the data.

A theoretical and experimental study of line broadening and merging is presented and suggested for diagnosis of high density laser plasmas. For densities larger than 1022 cm−3 the hydrogenlike sequence is reduced to four lines for the emitter ion with ZE = 9. The perturbation effects on the latter come mainly from the interaction with plasma ions and electrons (Stark effect, multipolar interactions, ionization by tunnel effect, polarization line shift …).