A prototype ultrasoft X-ray polychromator for impurity transport studies using a tracer-encapsulated solid pellet (TESPEL) has been recently developed at Johns Hopkins University and tested on the Large Helical Device. The system has high throughput with good spatial (a few cm) and spectral (0.1˜0.2 nm) resolution and millisecond time response for measuring faint charge-exchange recombination emissions from the fully stripped low-Z tracer impurity. The signals from the magnesium tracer deposited locally by TESPEL injection have been successfully obtained with the prototype polychromator.

抄録全体を表示

We propose an automobile engine driven by water-laser coupling without fuel. The automobile can load a solarpumped fiber laser or can be driven by ground-based lasers. The vehicle will be useful on other planets because the piston is in a closed system and the water will not be exhausted into a vacuum. In the preliminary experiment, we succeeded in driving a cylindrical piston of 0.2 g on top of water placed inside an acrylic pipe of 8 mm in inner diameter.

抄録全体を表示

Plasma current start-up and ramp-up to 10 kA have been demonstrated in the TST-2 spherical tokamak without the use of the central solenoid. Only the electron cyclotron wave (ECW) and the outer equilibrium field coils are used. The plasma current evolution depends on the poloidal coil arrangement. It is also demonstrated that the plasma current start-up can take place without the field null.

抄録全体を表示

Environmental assisted cracking (EAC) is one of the material issues for the reactor core components of light water power reactors(LWRs). Much experience and knowledge have been obtained about the EAC in the LWR field. They will be useful to prevent the EAC of water-cooled blanket systems of fusion reactors. For the austenitic stainless steels and the reduced-activation ferritic/martensitic steels, they clarifies that the EAC in a water-cooled blanket does not seem to be acritical issue. However, some uncertainties about influences on water temperatures, water chemistries and stress conditions may affect on the EAC. Considerations and further investigations elucidating the uncertainties are discussed.

抄録全体を表示

The ultimate purpose of fusion energy development is to utilize the produced fusion power mainly as electric power for ease of transmission and conversion. Irrespective of the type of fusion power plant, large circulating electric power should exist in the plant for the purpose of plasma heating, current drive, and soon. This chapter describes the typical electric power flow in fusion power plants to be built beyond ITER. In addition, the necessity of local energy storage and a high efficiency converter is discussed.

抄録全体を表示

The Ford Motor Company proposed the principle of the sodium-sulfur battery based on a beta-alumina solid electrolyte in 1967. Accordingly, sodium-sulfur battery technology was initially developed primarily for electric vehicle applications. Later, the Tokyo Electric Power Company (TEPCO) selected the sodium-sulfur battery technology as the preferred system for a dispersed utility energy storage system to substitute for the pumped hydro energy storage system. NGK Insulators, Ltd. (NGK) and TEPCO have jointly carried out the development of the sodium-sulfur battery since 1984. In April 2002, TEPCO and NGK made the sodium-sulfur battery for use as an energy storage system commercially available.

抄録全体を表示

The various applications of Vanadium Redox Battery (VRB) are described as large capacity energy storage system. Vanadium Redox Battery has been originally developed for load-levelling by storing electricity during periods of low demand and releasing electricity into the load at periods of high demand. Recently, it has been applied for uninterruptible power supply systems because of its high speed of response, ranging from complete blackouts to momentary voltage sags. It can be utilized for stabilizing the output of renewable energy sources. It has been verified to smooth fluctuations in the wind power output.

抄録全体を表示

Kinetic energy has been the energy well known since ancient times. The generator with a flywheel is an electric power amplifier that stores electric power and is made to generate large electric power at the short time, and used to be in a nuclear fusion institution. In recent years, the flywheel has been recognized an electric power tool for power stabilization. An example of application in the industry and in an electric power community is introduced. In addition, a characteristic application is developed despite the fact the energy efficiency of compressed air energy storage is generally poor.

抄録全体を表示

The principle, the structure, the features, the history, the state of art development, and the application of Superconducting Magnetic Energy Storage (SMES) are described.

抄録全体を表示

This paper introduces the loss reduction technology for power supply. Design and manufacture of the power supply for JT-60 was carried out using the high-power thyristor. Although the power supply for JT-60 was high-voltage and large-current, the power supply for ITER or a future nuclear fusion reactor system will be a low-voltage large-current type. It is very important to study the latest technical trend in low loss electric power conversion equipment using turn-off type power devices.

抄録全体を表示

Investigation of lightning discharges has about 250 years history. During these 250 years we have accumulated the knowledge, and the understanding of lightning physics has been done qualitatively. According to the author's understanding our interpretation and understanding about lightning physics is not sufficient. Moreover still we have newly discovered phenomena related with lightning discharge, like discharges from thundercloud top to the ionosphere named RedSprite. The investigation on lightning physics can be concluded as one of the attractive subjects, though it has long history.

抄録全体を表示

A scheme to suppress the ablative Rayleigh-Taylor (RT) instability using high-Z doped plastic target (brominated polystyrene;CHBr) has been proposed for a directly laser-driven IFE target. When an intense laser irradiates directly onto a high-Z doped target, radiation emitted from a corona plasma propagates and deposits locally its energy inside the target. The enhanced radiation forms the double-ablation structure, which consists of primaryelectron conduction ablation front and secondary radiative ablation front. The radiative ablation in the double-ablation structure has many advantages to suppress the growth of the RT instability in analogy of the indirect-drive approach, i.e. large mass ablation rate, long density scale length and low peak density. Two-dimensional (2D) hydrodynamic simulation code shows strong suppression of the RT instability in a brominated plastic (CHBr) target compared with that in an undoped polystyrene (CH) target. RT growth rates evaluated theoretically using the Betti-Goncharov procedure with one-dimensional(1D) radiation-hydrodynamic simulation are in good agreement with 2D simulation results. Several experiments were performed at the GEKKO XII- HIPER (High Intensity Plasma Experimental Research) laser facility. A trajectory of a laser-driven CHBr target observed in experiment was reproduced fairly well by 1D simulation code. The double-ablation structure formed inside a directly laser-driven CHBr target was clearly observed in experiments for the first time The strong suppression of the RT instability in the CHBr target was confirmed in experiments with face-on and side-on x-ray backlighting technique.

抄録全体を表示

Neoclassical tearing mode (NTM) stabilization by an electron cyclotron current drive (ECCD) has been studied by using the numerical model on the basis of the modified Rutherford equation coupled with the 1.5 D transport code and the EC code. The transport code solves the current diffusion equation, including the EC current profile. The background current modification and the resultant movement of rational surface by ECCD are taken into account. The EC code consists of the ray tracing method and the Fokker-Planck calculation. Undetermined parameters in themodified Rutherford equation are estimated from a comparison with the JT-60U experiments. Sensitivity of stabilization to the EC current location is investigated by simulation. The low EC current and peaked EC current profile mitigatesthe sensitivity, whereas the high EC current and peaked EC current profile moves the rational surface more largely via background current modification by the EC current and intensifies the sensitivity. The high EC current and broad EC current profile mitigates the sensitivity. The EC current necessary for the full stabilization is studied for ITER parameters. The necessary EC current strongly depends on the parameters of bootstrap current and ECCD terms in the modified Rutherford equation. Necessary ECCD power on ITER is evaluated on the basis of parameters estimated from comparisons with JT-60U experiments.

抄録全体を表示

The ion kinetic or skin depth effect on the relaxation of merging spheromaks to a field-reversed configuration (FRC) was investigated experimentally using varied S^* (the average number of the ion skin depth) from 0.5 to 10.The merging spheromaks relax either to an FRC (λ_p˜0) or to another spheromak (λ_p˜λ_Taylor), depending on whether their initial poloidal eigen value λ_pwas smaller or larger than the threshold value λ₀. The up-scaled TS-4 experiment under varied skin depths with several ion species revealed that the threshold value λ₀ for the relaxation to an FRC increased inversely with the S^* value. The decrease in S^* promoted the relaxation to an FRC, annihilating the magnetic helicity, in sharp contrast with the conventional Taylor relaxation. The low S^* relaxation to an FRC was observed to suppress the all low-n modes with the fast rotation of those modes.

抄録全体を表示

This study discusses the ionization mechanisms of sputtered titanium (Ti) in inductively coupled plasma (ICP)-assisted dc magnetron sputtering based on measurements and model analyses. Ionic and atomic densities of sputtered titanium were measured using an optical absorption method under an Ar pressure of 3.5 Pa against rf(13.56MHz) power applied to the inserted coil. A Langmuir probe provided measurements of electron densities against coil rf power, giving input parameters for model analyses. We adopted a model analysis method presented by J. Hopwood and F. Qian [J. Appl. Phys. 78, 758 (1995)]. Variations of ionic and atomic densities and ionization fractions against electron density from model calculation agreed with those obtained by measurements. The results showed clearly that electron impact ionization dominates ionization of sputtered titanium in high er electron density regions compared to Penning ionization through Ar metastable atoms. Penning ionization played an important role at the lower electron density region because of the longer time for radiative decay of Ar metastable atoms.

抄録全体を表示

Target fabrication technique is a key issue of laser fusion. We present a comprehensive, up-to-data compilation of laser fusion target fabrication and relating new materials. To achieve highly efficient laser implosion, organic and inorganic highly spherical millimeter-sized capsules and cryogenic hydrogen layers inside should be uniform in diameter and thickness within sub-micrometer ˜ nanometer error. Porous structured targets and molecular cluster targets are required for laser-plasma experiments and applications. Various technologies and new materials concerning above purposes are summarized including fast-ignition targets, equation-of-state measurement targets, high energy ion generation targets, etc.

抄録全体を表示