[en] The Institute of Laser Engineering at Osaka University outlines key issues of research, which are: the development of high-power drivers, pertinent pellet design for implosion by a large-scale computer code, pellet fabrication and handling, and diagnostic of the implosion process, with high resolution in space and time. Experimental facilities such as the GEKKO series and the CO₂-laser LEKKO series are discussed. A table and illustrations show energy drivers, the GEKKO XII optical arrangement, and the glass laser system of GEKKO XII. Fundamental processes in laser-plasma coupling, scaling of implosion presure, and implosion of the pellet and Cannonball target are described and accompanied by illustrations and photographs. The KONGOH project and activities at the Electrochemical Laboratory present research and progress on target experiments

[en] A new target is proposed which increases both the laser absorption rate and the hydrodynamic efficiency. This target consists of a light inner shell and a massive outer shell with pinholes for entry of the laser light. The acceleration mechanism is similar to that of a cannonball. A model for this acceleration is presented and compared with hydrodynamic simulations. (author)

[en] The interaction between laser and plasma, such as mode conversion of laser light to plasma wave, second harmonic generation at the resonance region (cut-off region), red shifted satellites with an isotopic effect in SHG-light and self-phase modulation of back-scattered light from the turning region were discussed. Also the anomolous absorption of relativistic electron beam in plasma was shown which is interpreted by the two-stream instability. (author)

No abstract available

No abstract available

[en] The neutronics in the blankets to be used for particle beam (LIB or HIB)-driven ICF reactors were examined in case of the spherical reactor vessels with dry wall reactor cavities. The calculations were performed with the one-dimensional neutron transport code ANISN-JR and the nuclear data GICX 40. To examine the scale merits or demerits of particle beam ICF reactor systems, three reactor cavities were designed. The inner radii of the cavities were 2.0, 5.0 and 15.0 m, and the fusion energy of each cavity is designed to be 30 MJ, 300 MJ or 3000 MJ. Two types of the blankets for the dry wall reactors were examined. In one blanket (A-type blanket), a 64 cm thick liquid Li layer was the first blanket zone. In another blanket (B-type blanket), there was a moderator made of graphite behind the first wall, and then the second SUS wall and a 64 cm thick Li layer existed. There were reflectors made of graphite outside the Li blankets in both types. The thermal deposition in the first wall in the A blanket was quite larger than that in the B blanket. The tritium breeding ratio was less than unity in the B-type blanket. The first wall (SUS 1) reduced the number of 14 MeV neutrons, and softened the neutron energy spectrum. (Kato, T.)

[en] The GEKKO XII is the twelve beam laser of 30kJ, 50TW in red and 20kJ, 35TW in green with two target chambers. The direct and the indirect implosion experiments, including the Cannonball targets and the cryogenic targets have been performed. The computer simulation of implosion processes has been fully compared with the experimental data. As for the drivers, different kinds of wavelength laser 0.25/sigma phi/m to 10.6/sigma phi/m as well as the ion beam are provided. They are used to investigate the various coupling processes in plasmas. The ignition condition of inertial confinement fusion has been discussed and a design concept for the laser fusion reactor is presented

[en] In order to show the importance of the international collaboration, the world progress in inertial confinement fusion is briefly reviewed setting particular attention on the Japanese efforts: direct drive target, indirect drive target, simulation analysis, and future prospects. The key issue for the next step is to set short wavelength lasers of mega-joule level as drivers to attain the high pellet gain required for a fusion reactor. Then the development of the reactor driver is the most crucial theme for the realization of an IFE reactor. 6 figs., 11 refs., 1 tab

[en] The computer code ''ABS'', which can calculate the absorption rate and distribution of the laser light in spherical symmetric plasmas has been developed. The dependences of the absorption rate and distribution on the focusing position and their wavelength dependences were obtained. It was found that with a shorter wavelength laser light, the absorption nonuniformity on the fusion pellets will be reduced as well as the absorption rate will increase. (author)

[en] The preliminary results of the experiment on chemi-ionization of uranium atoms in ground and laser-excited states are presented. Oxygen molecules were chosen as a reaction partner, since the experiment is preliminary and the handling of beams of oxygen molecules is easier than that of metal atoms. The beams of atoms and molecules were employed in crossed beam configuration to minimize the secondary reaction between reactants and produced ions. The apparatus comprises a main vacuum chamber, beam sources, a detection system, and two 10 in oil diffusion pumps and a 6 in oil diffusion pump if required. The beam of uranium atom was produced in the source consisting of a horizontally mounted tungsten crucible of hemispheric shape, 0.8 cm in diameter and 0.2 mm thick. The crucible connected to the tungsten belt was heated with current of 140 A at 7 V up to 2,400 deg. K at the central portion of the crucible. The vapor of uranium atoms from the crucible was collimated. The molecular beams were formed by the effusion from a rectangular multicapillary array made of metal foils. First, the uranium atom beam was observed through a RF quadrupole mass filter after ionization. Secondly, the uranium atom beam was intersected with the oxygen molecular beam. Ions produced by chemi-ionization were mass-analyzed and detected by the channel electron multiplier in counting mode. It seems likely that the probability of the decay from a potential curve of UO₂⁺ is greatly enhanced as compared with that from the potential curve of U + O₂. (Iwakiri, K.)