Rotating motion of a propagating LIB is analyzed in order to suppress the mixed mode of the Kelvin-Helmholtz instability, the tearing instability and the sausage instability by the action of a self-induced magnetic field in the axial direction. The beams are assumed to be charge-neutralized but not current-neutralized. The steady-state solutions of a propagating LIB with rotation are first obtained numerically. Through the dispersion relation with respect to the ikonal type of perturbations, which are added to the steady-state solutions, the growth rates of instabilities appearing in an LIB are obtained. It is concluded that if the mean rotating velocity of an LIB is comparable to the propagation velocity, in other words, if the induced magnetic field intensity in the axial direction is comparable to the magnetic field intensity in the azimuthal direction, the instability disappears in the propagating ion beam.

In the Ampfion diode, an ion beam is extracted from an anode plasma that is being pushed away from the cathode by a rising magnetic field. There is concern that ion heating in the anode plasma sheath may result in a significant ion beam divergence. To investigate this possibility, a comparison of Z pinches, θ pinches, and Ampfion is made. Ampfion sheath scenarios are examined and a simple argument is presented that indicates that an anomalous resistivity should develop. An upper bound estimate of the ion divergence is calculated, and examples are given for PBFA-II parameters. For a small radius diode with a high density anode plasma, it is shown that ion beam divergence due to plasma heating should not be a problem. For a large radius diode with a low density anode plasma, it is shown that ion beam divergence due to plasma heating is a problem, but that an Ampfion filtering mechanism should select a cool portion of the heated ions and help to alleviate this problem.

The radiation characteristics of a high-current hydrogen thyratron plasma have been modeled in order to study this aspect of the physics of the conductive phase of thyratron operation. The intensities and radiative energy efficiencies of the atomic and molecular systems have been calculated in detail. A model is developed that is useful for studies of photoemission. For discharge parameters Te ≈ 1 eV, ionization fraction of ∼10−2 and background density of 1016 cm−3, the total power of the emitted radiation is estimated to be of the order of 5% of the total input power during the conductive phase.

The shock pressures generated in the interaction of lasers and light ion beams with thin foils are calculated using a two-dimensional, axisymmetric hydrodynamic code. For lasers, finite spot sizes produce a significant decrease in the pressure generated, compared to previous 1-D estimates. The effect is closely related to the coupling of the critical density with the ablation surface and is less important at shorter wavelengths, the appropriate parameter being Iλ2. For 0·5 TW red light and a 100 μm radius spot pressures are limited to 30 Mb. Perturbations across the beam profile are discussed and it is demonstrated that beam uniformity of 30% (25% for green light) is required to achieve velocity modulation of less than 2%, such as would be necessary for an equation of state measurement.

For the larger targets used with light ion beams, two-dimensional effects prove to be less of a problem, and for high-Z materials the initial 1-D estimates of peak pressure are adequate. In order to obtain the shock planarity requisite for equation of state measurements in a high-Z target an intensity uniformity of ±15% would be required. However, use of a composite target enables this to be relaxed to ±25% whilst obtaining slightly higher pressures.

A new method for decreasing the operating temperature of copper vapor lasers (CVL) by pulsed injection of pure metal vapor into the active volume of the laser is described. The inductively produced copper plasma is accelerated by a pulsed magnetic field. As a result the laser operates at room temperature in a double-pulse mode. The population densities of both the ground and metastable states of copper atoms were derived from optical absorption measurements. The metastable level density decays rapidly while the ground-state densities exist up to 2 msec without noticeable changes. The scaling of this type of laser was studied. A 24 mJ output laser pulse of 65 ns duration was obtained for a laser tube 90 cm long and 10 cm bore. The advantages of the new CVL are discussed.

Some of the basic questions pertinent to the feasibility of heavy ion fusion are reconsidered with HIBALL I as the ‘standard’ HIF senario. The questions are quantified by developing scaling laws that enable the cost and capacity of HIBALL-like power plants to be varied.

Electron-beam sustained discharges can be used in opening and closing switch applications for producing bursts of energy in pulsed power systems. The incorporation of admixtures of attachers with low attachment rate at low values of E/N and high attachment rate at high values of E/N in the gaseous switch dielectric has been proposed to achieve low forward voltage drop in the conduction phase as well as rapid opening when the sustaining e-beam is terminated. This paper presents model calculations on the characteristics and transient behavior of an electron-beam sustained discharge in the high current density regime in N2. The influence of an attacher (N2O), with the property described above, and of the circuit parameters on the discharge is investigated as an illustrative example. The advantage of using such an attacher is demonstrated for the steady state conduction phases and for the opening phase, while the closing process is obstructed by the attacher. Additional possible control mechanisms, such as photodetachment to aid the closing process are discussed.

Ponderomotive force density of an HF field in a dispersive cold collisionless plasma is calculated using two independent methods: energy-momentum-stress tensor with the Abraham choice of momentum density and two-fluid hydrodynamics. The results appear to coincide and show that, even in isotropic plasma, terms proportional to the time derivative of the electric field amplitude appear in the ponderomotive force. It is demonstrated that, in the presence of relativistic electron beams, spatial dispersion is not negligible and the related correction to the ponderomotive force is calculated.

Heavy ion beam driven implosion of multilayered, single-shell targets for inertial confinement fusion are investigated by ID-simulation. Features characteristic of heavy ion energy deposition are studied. The ion beam energy and the tamper/absorber configuration which give optimum hydrodynamic efficiency and fuel ignition are found for a reactor-size target. A comparison of different pulse shapes with and without prepulse is presented. Implosion by a single-box pulse is found to give superior hydrodynamic efficiency and spherical stability. In addition to these specific results, general features of ion driven implosions are discussed and a brief description of the target code MINIHY is given.

The development of high power ion diodes for inertial confinement fusion is in progress on the PBFA I accelerator. The three main types of magnetically-insulated ion diodes, the Applied-B, Hybrid, and Pinch Reflex diodes, are compared. This paper presents the results from the first series of tests of the Hybrid diode.

Recent progress on accelerator and systems studies carried out in the framework of a national program on heavy ion fusion is reviewed. Plans for future investigations aiming at the basic aspects of inertial confinement with heavy ion beams are discussed.

Because of the large number of X-ray photons which will be emitted per unit solid angle and wavelength interval, laser generated plasmas have good prospects as X-ray sources for time-resolved diffraction experiments in solid state research. Starting from this a modified two-crystal diffractometer will be described, which uses the particular advantages of laser plasmas as X-ray flash sources. Requirements for the source will be determined and discussed.

Simple arguments are used to construct a model to explain the conversion efficiency of absorbed laser energy into soft X-rays from laser-irradiated targets. In this model, we postulate that the energy available for conversion is bounded at some low irradiance limit by heat conduction away from the laser heated spot, while at some high irradiance limit it is bounded by the energy lost in plasma blowoff. Consequently, at some appropriate laser intensity, where the sum energy of the conduction and blowoff losses is at a minimum, the X-ray conversion efficiency should reach a maximum. A specific example for gold disk targets irradiated by 0·53 μm laser light will be treated. Simple heuristic scalings of blowoff and conduction as functions of laser intensity are obtained.

The present paper presents experimental results of the transverse and longitudinal phase volume for the expanding multicharged ions in laser produced plasma, created by focusing a CO2-laser (beam) onto a Pb207 target. The total number of Pb207 ions (with Z = 1 or 2 and Z = 6), the ion current duration and amplitude at a distance of 1 m from the laser target within 10−2 steradians are determined. The measured experimental parameters of the laser heavy ion source are compared with the driver requirement for the heavy ion inertial fusion (HIIF) programme.

The phenomena observed in the experiment confirm the results of numerical calculations using a two temperature hydrodynamic programme.

In this paper recent simulation studies at GSI on instabilities and emittance growth for different particle distributions and initial experimental results with the 12-lens section of the University of Maryland electron beam transport channel are reviewed.

We review some equations that must be satisfied when generating rf-linac/storage-ring systems for heavy ion fusion. To treat the phase-space constraints, we derive new formulae for separate transverse and longitudinal available dilution factors in terms of parameters of the rf-linac/storage-ring system. We outline a method for generating accelerator designs that satisfy target, current amplification, phase-space, and spacecharge constraints.

For real-time diffraction experiments in X-ray crystal research a simplified model is chosen to describe laser-generated plasmas. This enables a rough estimate of the optimum laser plasma parameters necessary to maximize the line emission of highly ionized species. Furthermore, the use of the hot electron spectrum of laser plasmas to generate ultrashort Kα-emission is discussed.

In recent years there has been considerable effort to understand the equation of state (EOS) of materials, particularly at high pressures and temperatures. Such studies have direct applications in the laser fusion problem where materials are subjected to radiation induced shock waves which compress material to over 100 times the normal density at temperatures up to 100 million degrees (e.g. Hora 1981). Among the various models which describe the electronic thermodynamic functions in highly compressed matter, the Thomas–Fermi model is the one most often used in hydrodynamic codes, e.g. in the simulation of the inertial confinement fusion problem.

A self-consistent model for the beamline of a light ion beam fusion reactor is presented. Code calculations for the region from the end of the Magnetically Insulated Vacuum Transmission Line (MITL) entering the ion diode to the energy output from fusion reactions in the pellet fuel are described. The design utilises state-of-the-art pulsed power and a concept for repetitive operation of a pinch reflex diode. Deuterium beams are launched at 6·3 MV and are transmitted through preionized channels. Overall energy transfer efficiency from electrical source to pellet is 20%. The principal developments required are beam brightness, which scales from present day experiments, and repetitive diodes.