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.

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.

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.

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.

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.

A novel method of utilizing fluorescence generated from the products of nuclear reactions offers the prospect of compact, high efficiency, multi-megajoule lasers. To overcome the problems associated with traditional laser (or energy converter)-fissile material interfaces, such as a uranium coating (low power density and low efficiency) or a gaseous uranium compound (low power density and deleterious effects on the laser kinetics and photon transport), a method suggested elsewhere of employing a reactor using a uranium aerosol fuel, interspersed with a fluorescer medium, is briefly reviewed. The charged particles produced by nuclear reactions in the fuel produce fluorescence in the core region of the reactor, through interactions with the fluorescer. This fluorescence can then be concentrated, to increase the effective power density in the laser medium, and used to drive a photolytic laser.

One key issue in the above process is the charged particle spectrum from the fissile aerosol. These issues can be addressed theoretically based on the Dirac chord length distribution technique and an Arcen's function. The charged particle spectrum from a UO2 coating has been generated and benchmarked with the experimental data of Kahn et al., and Redmond et al. Agreement is generally good except near the end of the fission fragment tracks. The validity of this simple technique in approximating the rate of ion energy loss lends confidence to the generation of fission fragment spectra for other geometries (i.e. spherical in which transport efficiencies of over 60% appear achievable) using U, UO2 and U3O8. Work is also extended to the case of B-10 in a variety of configurations which are frequently used in modern energy conversion experimental devices.

Absorption, reflection and scattering of laser radiation have been studied in experiments with oblique incidence of Nd glass laser beams on plane massive targets of polyethylene, aluminium and copper. Time behaviour of 2ω and 3/2;ω harmonic intensities and their angular distributions were measured along with plasma X-ray spectra in the flux density range 1013 to 3×1014 W/cm2 for 3.5 nsec laser pulses. Comparison of the experimental data with the results of the theoretical analysis and numerical calculations is presented and relatively strong absorption of about 10% is estimated in the quarter critical density region of the plasma corona due to the two-plasmon decay instability growth. The hard X-ray component in the X-ray spectrum disappears at large angles of incidence, hence the supra-thermal electron generation and two-plasmon instability are proven to be coupled phenomena.

An electron gun is being developed which should substantially improve the normalized current density in medium energy pulsed linacs. The gun will accelerate and pre-bunch electrons from a LaB6 cathode using the high electric field in a resonant microwave cavity.

A one-dimensional model is used to study the hydrodynamic response of thin foils to bombardment by an intense proton beam. The beam targets are single- and multilayer planar foils of gold and polystyrene. The main conclusion of the study is that the efficiency of conversion of incident beam energy to directed kinetic energy of the target is maximized by using a multilayer design. For beam parameters associated with the Gamble II device at the Naval Research Laboratory, the simulations yield payload velocities of over 5 cm/μs and energy conversion efficiencies of over 30%. We discus the implications of these results for inertial confinement fusion research.

A new electro-optical technique has been developed in which a streak camera is coupled to a Pockels cell with a fast risetime. This technique can improve the time resolution of the high voltages observed in laser produced plasmas between one and two orders of magnitude in comparison to the best oscilloscope measurements. This method should prove useful in confirming the existence of electrostatic fields and elucidating the structure of the wave instabilities found in laser produced plasmas.

Excitation of large amplitude electron plasma waves by laser by P. Mulser and H. Schnabl in: Laser and Particle Beams (1983) vol. 1, part 4, pp. 379–394.