[en] Implosion hydrodynamics are examined, from the conditions in the imploded target to the initial target configuration and the driver performance. The subject is discussed under the topic headings: inertial configuration, thermonuclear fusion processes, ignition model, shock waves, acceleration by a constant pressure, spherical shock waves and imploding flows, drive pressure requirements, pulse shaping, pressure generation by lasers and ion beams, symmetry and hydrodynamic stability and typical target designs. (U.K.)

[en] In a laser driven ablation plasma the ablation process leads to a significant cooling of the ions. The reduced ion temperature leads to large Brillouin reflectivities which may be close to 100% at laser wavelengths of 1μ. (author)

[en] Large amplitude Langmuir waves with a phase velocity close to the speed of light may be generated by the beat frequency of two co-propagating laser waves in an underdense plasma. Numerical simulations of the saturation of these waves show that relativistic detuning limits the wave growth but fails to give quantitative agreement with earlier work. Reasons for this disagreement are discussed and the numerical work is found to agree with more recent calculations. (author)

[en] The essential features of a laser fusion pellet are shown to be a high density, high pressure core, with a central hot spot. A high degree of symmetry in the implosion is required and the related subjects of symmetry and hydrodynamics stability are briefly discussed. The laser plasma interaction process is important in producing high absorption efficiency without preheating the core by fast electrons. (author)

[en] A modified form of the computer code MEDUSA has been used to study the heating and hydrodynamic response of hollow spherical shells irradiated by various ion beams. The ion beams are considerably more effective than laser beams in generating the large pressures required for inertial confinement fusion targets. (author)

[en] Radionuclide releases to the environment from Battelle's West Jefferson Nuclear Sciences and King Avenue Sites were monitored for CY 1978. This included air and water emissions from the West Jefferson and King Avenue Sites and water, grass, fish, food crop, sediment, and soil samples taken from the area surrounding the West Jefferson Site. Nonradioactive effluents in water discharged from the West Jefferson Site were also monitored

[en] In order to compress matter to high densities by the application of intense pulses of laser energy it is necessary for the implosion of the target to be both stable and spherical. This imposes certain constraints on the uniformity of illumination of the target, and, this in turn places requirements on the illuminating optics and the laser beam quality. This report discusses the uniformity of illumination of a spherical target as provided by a variety of optical systems and for different numbers of laser beams and beam profiles. The results are compared with similar conclusions obtained by other workers. An alternative presentation of the calculations is given which is believed to be a more realistic estimate of the uniformity. Comments are made on the approximations that have been assumed and the results likely to be obtained from the full treatment are discussed. The effects of this non-uniform illumination on the target implosion are considered using the linear theory of the Rayleigh-Taylor instability. Finally, comments are made on other factors of a more practical nature which also govern the final choice of illumination system and the scope of experiments made possible by such a system. (author)

[en] The 1D Lagrangian fluid code MEDUSA has been used to study the process of laser driven ablation for a variety of irradiances and laser wavelengths. Values are given for physically important parameters such as ablation pressure and coronal temperature as a function of wavelength and irradiance. The effect of changing the physical assumptions in MEDUSA is discussed and appropriate comparison is made with analytic models. An attempt is made to deduce optimal values of laser wavelength and irradiance. (author)

[en] The transport of energy by X-ray photons has been included in the lD Lagrangian hydrodynamics code, MEDUSA. Calculations of the implosion by 0.53 μm laser irradiation of plastic and glass microballoons of current interest at the Central Laser Facility show that radiation preheats the fill gas and alters the temperature and density profiles during the implosion. A lower maximum gas temperature is obtained and this results, for a DT gas fill, in a greatly reduced neutron yield. (author)

[en] The Fokker-Planck equation has been solved numerically in one spatial and two velocity dimensions in order to study thermal conduction in large temperature gradients. An initially cold plasma is heated at one end of the spatial grid producing temperature gradients with scale lengths of a few times the electron mean free path. The heat flow is an order of magnitude smaller than that predicted by the classical theory which is valid in the limit of small temperature gradients. (author)