In a fusion reactor, the blanket performs the important functions of tritium breeding, heat production, and shielding. System integration must be considered in the blanket’s development and design. This report stresses the importance of system integration and describes recent developments in the materials of the blanket system as well as relevant issues in system integration.

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Many kinds of fullerenes and nanotubes are produced efficiently by the arc discharge method, which is most effective method for producing large quantities of these materials. In this paper, various methods of fullerene production, carbon cluster families produced by arc discharges, basic processes and characteristics of fullerene synthesis, and the development and applications of arc production are introduced and discussed.

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Endohedral metallofullerenes are novel forms of fullerene-related materials which can encapsulate various types of metal atom(s) within their carbon cages. Upon encapsulation of metal atoms, these fullerenes exhibit unique structural features as well as various unique properties with respect to empty fullerenes. Recent progress on their bulk production, elucidation of their structures, and some electronic properties of endohedral metallofullerenes is described.

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This paper characterizes and describes the growth of carbon nanotubes (multiwall and single-wall) and nanocapsules produced by electric arc discharge. For the preparation of multiwall nanotubes, an electrode of pure carbon is evaporated in helium gas, while single-wall nanotubes are produced with the aid of metal catalysts. When carbon is evaporated together with metals, carbon nanocages filled with fine metal particles (called “nanocapsules”) are produced in addition to single-wall nanotubes. The growth of nanotubes and nanocapsules is discussed. Finally, the application of nanotubes in a field emission electron source (cold cathode) is demonstrated.

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The advantages and disadvantages of the arc discharge method for preparing fullerenes are briefly discussed in comparison with conventional combustion method. Ways are being sought to overcome inherent disadvantages of the combustion methods by learning from nature. The search, for natural fullerenes led us to discovery of a novel coal which not only contains abnormally large amounts of C₆₀, but also shows unique TEM images which closely resemble those of soot. A series of examinations led us to conclude that carbon blacks are the ideal raw material for the production of C₆₀ and also probably carbon nano-onions as well,

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Simulations of the molecular dynamics of the fullerene formation process are described. Starting from 500 randomly distributed gas-phase carbon atoms, the formation of cage-like carbon structure is demonstrated. Combined with annealing simulations of imperfect cage structures with the intension of forming perfect C₆₀ and C₇₀ structures, a fullerene formation model through random-cage structure is proposed. In addition, a simulation of the molecular dynamics of endohedral metallofullerene formation is also demonstrated.

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A fullerene plasma consisting of positive potassium ions, huge negative C₆₀ ions, and residual electrons is generated in a Q machine, which has traditionally been used for plasma physics studies, under the influence of the mass production of fullerenes by an arc discharge method. The fullerene plasma shows novel behaviors associated with collective phenomena such as wave, instability, cross-field transport, and structure formation, Drastic changes in thin-film structure and the quality of K-C₆₀ compounds are observed, and endohedral metallofullerene K@C₆₀ is effectively formed in accordance with the bias control of the fluxes and energies of K⁺ and C₆₀^- flowing into a substrate immersed in this plasma.

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The formation of electrostatic potential in a tandem mirror is reviewed. The plug potential and thermal barrier potential formations are first presented. The continuous potential profile across the mirror throat and the plug is discussed, which is required to avoid the formation of a sheath potential. The neoclassical radial transport is shown finally in order to calculate the potential radial profile in the central cell of a tandem mirror with finite endplate resistance.

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Emission of He I lines (668nm, 706 nm and 728nm) has been simultaneously observed in the JT-60U divertor plasma. From calculations using a collisional-radiative model, intensity ratios of these He I lines are considered to be useful to measure electron temperature and density. In order to evaluate the feasibility of the intensity ratio method for temperature and density measurements, the measured intensity ratios are compared with those calculated from the temperature and density measured with Langmuir probes. As a result, the measured intensity ratios are well reproduced by the calculations. The discrepancies in the ratios I (728nm)/I (706nm) and I (668 nm)/I (728nm) between the measurements and calculations are about 12%.

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The particle transport for several impurity ion species was investigated in reversed shear and ELMy H-mode plasmas on JT-60U. Particle diffusivity for neon was evaluated from gas-puffing modulation experiments; the diffusivity was smaller by one order of magnitude at the internal transport barrier in reversed shear plasmas than in ELMy H-mode plasmas. An increase of the inward pinch velocity for neon was observed at the internal transport barrier in the reversed shear plasma. The particle transport coefficients at the internal transport barrier were compared for neon, carbon and helium. The particle diffusivity was almost the same for all ions, while the inward pinch velocity was larger for ions having higher charge state.

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In the period from 1993-98, several Natural Diamond Detectors (NDD) developed in Russia were used for D-T neutron spectra measurements during tritium experiments on the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET), in triton burn-up studies on JT-60U and for fast charge exchange atom spectrometry during ion cyclotron resonance heating on TFTR and neutral beam injection on the Large Helical Device (LHD). Some results of this international activity will be presented in this review paper. A number of unique properties makes the NDD very promising for neutron and high energy particles spectrometry and flux monitoring in future burning plasma and other high energy physics experiments.

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