[en] Applications for high current (> 1 kA) ion beams are increasing. They include hardening of material surfaces, transmutation of radioactive waste, cancer treatment, and possibly driving fusion reactions to create energy. The space-charge of ions limits the current that can be accelerated in a conventional ion linear accelerator (linac). Furthermore, the accelerating electric field must be kept low enough to avoid the generation and acceleration of counter-streaming electrons. These limitations have resulted in ion accelerator designs that employ long beam lines and would be expensive to build. Space-charge neutralization and magnetic insulation of the acceleration gaps could substantially reduce these two limitations, but at the expense of increasing the complexity of the beam physics. We present theory and experiments to determine the degree of charge-neutralization that can be achieved in various environments found in ion accelerators. Our results suggest that, for high current applications, space-charge neutralization could be used to improve on the conventional ion accelerator technology. There are two basic magnetic field geometries that can be used to insulate the accelerating gaps, a radial field or a cusp field. We will present studies related to both of these geometries. We shall also present numerical simulations of open-quotes multicuspclose quotes accelerator that would deliver potassium ions at 400 MeV with a total beam power of approximately 40 TW. Such an accelerator could be used to drive fusion

[en] We are presently adding the capability to irradiate indirectly-driven Nova targets with two rings of illumination inside each end of the hohlraum for studies of time-dependent second Legendre (P2) and time- integrated fourth Legendre (P4) flux asymmetry control. The rings will be formed with specially designed kinoform phase plates (KPPs), which will direct each half of each beam into two separate rings that are nearly uniform azimuthally. The timing and temporal pulse shape of the outer rings will be controlled independently from those of the inner rings, allowing for phasing of the pulse shapes to control time dependent asymmetry. Modifications to the incident beam diagnostics (IBDS) will enable us to verify that acceptable levels of power balance among the contributing segments of each ring have been achieved on each shot. Current techniques for precision beam pointing and timing are expected to be sufficiently accurate for these experiments. We present a design for an affordable retrofit to achieve beam phasing on Nova, results of a simplified demonstration, and calculations highlighting the anticipated benefits

[en] Larege growth Rayleigh-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of planar fluorosilicone foils with 50-μm wavelength initial surface perturbations. Foils with large-amplitude initial perturbation quickly enter the nonlinear RT regime, and show little growth. Foils with very-small-amplitude initial perturbations grow exponentially for longer, and show much larger growth factors. From comparisons with two-dimensional computer simulations, we deduce that the observed growth is about 60% of that expected for classical RT growth

[en] A simple analytical mode for the implosion of very thin spherical shell targets filled with fuel gas is developed. The shock trajectory in the fuel is described consistently with the shell acceleration, and two dimensionless parameters which govern the complete dynamics are found. The model applies to recent experiments focused on high neutron yield and provides a simple description of the main physical phenomena, which is in agreement with simulation and experiments. (author)

[en] Direct drive implosion experiments on the GEKKO XII laser have demonstrated the high density compression needed for thermonuclear ignition and burning. Deuterated and tritiated (D-T) plastic hollow shell targets, which have a design similar to that of cryogenic D-T shell targets, have been compressed to densities of 600 g/cm³. The irradiation non-uniformity in these experiments was significantly reduced to a level of <5% (root mean square values) by introducing random phase plates. The target irregularity was controlled to a 1% level. The target areal densities were directly measured by a carefully calibrated neutron activation technique. The extension of this result to cryogenic fuel targets with the same hollow shell structure has been intensively studied experimentally and theoretically. (author). 14 refs, 6 figs

[en] Under the demands of fundamental research, the accelerator community has responded with a number of impressive fundamental developments. New types of accelerators and colliders have permitted a tremendous progress in the understanding of subnuclear physics. It is very likely that such a progress may lead also to practical applications in a number of other fields and in particular in that of energy production. (orig.)

[en] Conceptual designs for two inertial confinement fusion power plants are being developed for DOE. The reactor designs, Prometheus-L and -H, respectively use the promising KrF and the heavy ion drivers. Safety, environmental impact, performance, and economics all have a strong influence on the system choices. In this paper, specific design choices are discussed which lead to the preliminary design points for both power plants

[en] In this paper we present one-dimensional numerical simulations of compression and burn of a high-gain indirect drive inertial fusion target suitable for use in a reactor system. The target consists of a capsule that contains 4.45 mg of DT fuel and the capsule is enclosed in a solid gold casing. The inner radius of the casing is twice larger than the outer radius of the capsule so that the inner surface area of the hohlraum wall is four times larger than the capsule surface area. The cavity is filled with a homogeneous radiation field whose intensity increases in time in an appropriate manner reaching a maximum radiation temperature of 300 eV. The capsule is driven to thermonuclear burn by this radiation field. The target (capsule + casing) absorbs an input energy of about 5.6 MJ and the implosion produces an output energy of 720 MJ so that the overall energy gain of this target is of the order of 130. (orig.)

[en] A method to determine the scaling law of the electron thermal conductivity with modulating heat pulses is proposed. Relation between temperature phase lag and parameters is established, from which the electron thermal conductivity in center region of CT-6B tokamak is determined

[en] Stimulated Raman scattering is observed when high-pressure H₂ is pumped by KrF laser. The Stokes beams and anti-Stokes beams are compressed. The first Stokes beam is 1/3 of that of the pumping beam. And the effect of buffer gas on conversion efficiency of Stokes beams is studied