The kinetic stability properties of relativistic nonneutral electron flow in planar diode geometry are examined for extraordinary-mode perturbations about the self-consistent Vlasov equilibrium . Here, the cathode is located at x = 0; the anode is located at x = d the outer edge of the electron layer is located at is the equilibrium flow velocity in the x-direction; n^b is the electron density at the cathode (x = 0); and is the axial magnetic field, with const. in the vacuum region (xb < x ≤ d). The extraordinary-mode eigenvalue equation, derived in a companion paper for low-frequency, long-wavelength perturbations, is solved exactly. This leads to a formal dispersion relation, which can be used to determine the complex eigenfrequency ω over a wide range of system parameters and wavenumber k in the y-direction. The formal dispersion relation is further simplified for and , assuming low-frequency perturbations about a tenuous electron layer with and . Here, , and , where denotes the average equilibrium orbit, and [γ(x) − 1]mc2 is the average kinematic energy of an electron fluid element. The resulting approximate dispersion relation is solved numerically over a wide range of system parameters to determine the detailed dependence of stability properties on electromagnetic effects, layer thickness, and electron energy, as measured by , and γb − 1, respectively. Here, γb = γ(xb) denotes the electron energy at the outer edge of the electron layer. As a general remark, it is found that increasing the electron energy (γb − 1), increasing the strength of electromagnetic effects , and/or decreasing the layer thickness (xb/d) all have a stabilizing influence.

Recent progress of pellet implosion research is remarkable in the obtainment of a high density (100 times solid density) and a high temperature plasma (which produces thermonuclear neutrons of 1013 per shot or a pellet gain of 0·2%) and in the corresponding understanding of the implosion physics. The data bases for laser fusion have been accumulated in preparation for a fusion ignition experiment and the achievement of break-even condition, which is estimated to be possible with 100 kJ blue laser.

The recent progress of driver technology, such as new types of solid state lasers, excimer laser, light ion beam (LIB), heavy ion beam (HIB) and free electron laser, now enabled us to design a high pellet gain experiment with a MJ driver.

KrF and other short wavelength lasers are ideal candidates for producing hot dense plasmas since the laser energy can be absorbed with high efficiency by classical mechanisms, thereby virtually eliminating anomalous absorption and the production of non-thermal electrons. A high power KrF laser system employing optical beam multiplexing and stimulated Brillouin scattering to produce pulses as short as 1 ns and focused intensities on target of 1011−1014 W/cm2 has been developed for producing such plasmas and studying laser/plasma interaction phenomena. A variety of studies on absorption, transport, ablation, X-ray conversion and stimulated scattering instabilities have been pursued with this ¼ μm laser on single atomic number and multi-layer targets. This paper briefly describes some of the features of the KrF laser system and highlights some of the characteristics of the hot dense plasmas produced.

A model for the hydrodynamics of a layer-structured target impinged by an intense ion beam is presented. For some power law time pulses, the flow in the absorber region, which is entirely different from that in the tamper, becomes self-similar for planar geometries. Scaling laws for the ablation pressure and the implosion velocity have been obtained from the analysis.

The LIBRA light ion beam fusion commerical reactor study is a self-consistent conceptual design of a 330 MWe power plant with an accompanying economic analysis. Fusion targets are imploded by 4 MJ shaped pulses of 30 MeV Li ions at a rate of 3 Hz. The target gain is 80, leading to a yield of 320 MJ. The high intensity part of the ion pulse is delivered by 16 diodes through 16 separate z-pinch plasma channels formed in lOO torr of helium with trace amounts of lithium. The blanket is an array of porous flexible silicon carbide tubes with Li17Pb83 flowing downward through them. These tubes (INPORT units) shield the target chamber wall from both neutron damage and the shock overpressure of the target explosion. The target chamber is a right circular cylinder, 8·7 meters in diameter. The target chamber is ‘self-pumped’ by the target explosion generated overpressure into a surge tank partially filled with liquid that surrounds the target chamber. This scheme refreshes the chamber at the desired 3 Hz frequency without excessive pumping demands. The blanket multiplication is 1·2 and the tritium breeding ratio is 1·4. The direct capital cost of LIBRA is estimated to be $2200/kWe.

The effect of thermal flux transport inhibition on the coupling of the spherical dense pellet core with the hot electron halo produced at the plasma resonance layer has been investigated. The analytic expressions for the core-corona coupling and the optimum temperature of the overlapping region (at which this coupling is maximum) have been derived as a function of ‘flux limit’ parameter and the laser wavelength. Relevant calculations indicate that the core-corona coupling is sensitive to the mean electron temperature and the scaling of its maximum value with the laser wavelength remains absolutely unaffected by plasma ablation. The subsequent results on laser wavelength scaling are compared and contrasted with the predictions of other investigations. The heat transfer from the hot electron cloud to the dense core can be increased by an order of magnitude in case of the uninhibited flux.

Progress in high-brightness excimer lasers and in optical angular multiplexing of excimer lasers presents an opportunity to provide very intense pumping of X-ray sources, both in favorable geometry and in traveling waves, all at low cost. The traveling-wave strategy can be tailored to the parameters of the system to be pumped. This design option can be of great importance for systems lasing at wavelengths in the kilovolt regime where upper level lifetimes are short, and where mirror technology is presently tenuous. Features of several design strategies are explored.

We present two partial models applied in the atomic physics subpackage used in numerical simulations of pulsed-source-driven, non-ideal high-parameter plasmas. These are an electron EOS model and a model for electron conductivity coefficient calculations. The EOS model uses Dharma-Wardana exchange and a correlation correction that depends on both electron density and temperature. The electron thermal and electrical conductivity calculations are based on the Balescu-Lenard equation.

The Laboratory Microfusion Facility (LMF) has been proposed to study Inertial Confinement Fusion (ICF) targets with reactor-grade gains. An advanced solid-state laser is the prime candidate as the driver for the LMF. However, here we present a conceptual design for an alternate approach using a Nuclear Pumped Laser (NPL).

A pulsed fission reactor is used to excite an oxygen-iodine laser in this design, based on preliminary data on nuclear pumping of O2(1δ). Although a working NPL of this specific type has not yet been assembled, we believe this concept holds great potential, both as a test facility driver and as a future power reactor.

An overview is given of recent progress in the industrial applications of intense pulse power and associated particle beams, except for activities in inertial confinement fusion. In particular, several topics are discussed which relate to the applications in the R&D of materials, the excitation of short wavelength lasers, the generation of charged particle beams, and the development of plasma X-ray sources.

I. Applications in material processing. If intense pulsed charged particle beams are directed onto materials, only their surfaces where the beam energy is deposited are quickly heated up to very high temperatures. Using the pulsed beam in this way, we might expect to apply them in R&D of materials. Several novel attempts have been made, e.g., on the preparation of thin films by use of a high-density high-temperature plasma, surface modification by surface heating, and ion-beam mixing of multi-layers by use of the focused electron or ion beams, and so on. Furthermore, experimental studies have been done on the surface modification by ion implantation and the evaluation of the damage due to the irradiation by ion beams.

II. Applications in the excitation of short wavelength lasers. Activities in the excitation of high-power, short wavelength lasers by using electron beams or ion beams have increased considerably.

III. Applications in the generation of charged particle beams, and the development of plasma X-ray source. With regard to new accelerator technologies, several attempts are underway on the application of the modified betatron or the development of a convergent electron beam accelerator with a plasma cathode.

The conventional implosion scheme for high gain and high density compression depends upon the piston action of an accelerated heavy pusher. However, the contact surface between the pusher and the fuel layer is very unstable in the stagnation phase. In this paper, the laser pulse tailoring and the scaling laws for pellet gain, fuel ρR, etc. are discussed under the condition of very weak piston action of the pusher. The scaling laws indicate that the fuel will be ignited by 100 kJ, 0·35 μm wavelength laser irradiation.

In this paper we have theoretically studied the field distributions and resonance absorption in a laser-produced plasma filament. Under the condition of the cold plasma we derive the field equations, as well as their analytical solutions, to the radial and axial components of the electric field. Then, by the numerical calculations, we find that there exists a tunnel effect along the radial direction of the filament, i.e., the electric field reaches a maximum near the radial resonance point r0. Thus, the curves of variance of the radial and axial field components are obtained.

Periodical short pulse trains were observed in the oscillation of the waveguide mode free electron laser, which could be explained as a self mode-lock oscillation of the free electron laser.

The spectra of the spontaneous emission and the induced absorption were observed, which were in good agreement with theoretical calculations.

The energy spread of the relativistic electron beam was measured using Thomson back scattering from a high power CO2, laser.

The linear conversion theory of laser produced plasma filaments is studied in this paper. By calculations for the energy flux of the second harmonic emission on the basis of the planar wave-plasma interaction model, it has been found that there exists no 2ω0 harmonic emission in the direction perpendicular to the incident laser, in contradiction with the experiments. Therefore, we have proposed a linear conversion theory on the second harmonic emission from a plasma filament and discovered the intense 2ω0 harmonic emission in the direction perpendicular to the incident laser, which is in agreement with the experiments.

The implosion dynamics of experiments with high-aspect-ratio laser-driven targets are re-examined by taking account of long ion-mean-free paths. The mean-free path is found to be comparable to the fuel size and this can cause a significant departure from a fluid-like description. One of such effects stemming from the long ion-mean-free path; namely, real viscosity, seriously changes the results; the compression ratio becomes 5 times smaller with this real viscosity. In addition to this, inclusion of non-LTE (local thermodynamic equilibrium) atomic process is shown to critically determine the implosion dynamics because of bound-free opacity associated with a small fraction of hydrogen-like ions.

Cluster beams may be produced by screening out the core portion of a partially condensed supersonic jet and introducing it into a high vacuum chamber. Potential applications of such beams are reported here and include accelerator targets, plasma generation, nuclear fuel injection into fusion devices, and production of thin layers for microelectronics and optics.

Pulsed laser induced damage of optical thin films is, in general, initiated by the absorption of laser radiation by imperfections in the films or at interfaces between film layers and/or the substrate. A heat flow analysis of this process stresses the importance that the thermal conductivity of both the thin film host and that of the substrate play in establishing the laser-induced damage threshold. Unfortunately, recent work, which will be reviewed in this presentation, indicates that the thermal conductivity of thin films can be several orders of magnitude lower than that of the corresponding material in bulk form. This situation arises as a consequence of the film structure resulting principally from the deposition process. The importance of thermal conductivity will be compared to parameters such as absorption mechanisms, film materials, composition, and other variables. Its implication for the ultimate optical strength of materials and the direction in which thin film research and processing should proceed will be highlighted.

Experimental studies on high power ∼ 10 μs electron beam generation have been carried out. High efficiency (about 75%) of energy transfer from a capacitor storage to the electron beam with total energy about 150 kJ has been attained.

A wide applicaton of high-power braking x-radiation and electron beams is obstructed at present by the absence of compact, screened, inexpensive and reliable generators capable of producing an electron energy of ∼1·5 MeV and a dose rate to objects a few centimeters in size of ∼107 A/kg. This paper presents results from experiments carried out on an X-ray generator with an accelerating voltage of up to 1·8 MV, which meets the above requirements in performance.

The interaction between particles and an electromagnetic (EM) wave is investigated numerically in the system of particle Vp × B acceleration by the EM wave. Numerical simulations show that the particle acceleration mechanism works well in the case of the appropriate number density of the imposed particles. When the interaction between particles and the wave is too strong, a part of the trapped and accelerated particles is detrapped. A condition is also presented for the efficient particle acceleration and trapping by the EM wave.