A quasi-equilibrium and recirculating compression scheme has been suggested for the beam bunching of heavy ion fusion. The recirculating beam buncher consists of induction linacs and bending sections. Induction modulators apply the velocity tilt for beam compression. The applied voltage is controlled so as to moderate the velocity tilt by the space charge force before the bending sections. As a result, the repulsion force of the beam is generally balanced with the bunching force during the compression process. Consequently, while the beam is gradually compressed under a quasi-equilibrium condition, the transverse mismatch from the velocity tilt of the bunching beam is suppressed to an allowable level.

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The oxidation of molybdenum by oxygen plasma was studied. The oxygen plasma was discharged by helicon wave at the frequency of 18.1 MHz and at the power of 200W. The weight change of molybdenum in oxygen plasma was measured at 400 °C and at oxygen pressure of 5 Pa. The specimen was found to be oxidized and to lose it's weight drastically with the oxygen plasma, while the weight change of the specimen in the oxidation without plasma was not observed under the same conditions. The energetic species of oxygen atoms generated by rf plasma is regarded to accelerate the oxidation of molybdenum and the oxidation leads to the formation of volatile molybdenum trioxide at the surface.

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The helicon discharge has attracted growing interest as a dense plasma source (order of 10¹³ cm^-3) for basic research and various practical applications. However, the problem of a high efficiency production mechanism for the helicon discharge remains to be solved. This mechanism is discussed in terms of a comparison between experimental and computed results, focusing on a mode conversion theory from helicons into slow waves (Trivelpiece-Gould mode). In addition, recent topics regarding helicon wave physics as well as plasma applications and future trends in utilizing this wave are highlighted.

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Thermoelectric system has various merits for use in energy conversion because the temperature difference is only required to generate electric power and there are not movable parts in the system. However, thermoelectric system is not so popular in civil use because its energy conversion efficiency is not high in the present time. But if we consider the exergy flow even in a conventional turbine generator, the turbine generator system can not use energy completely, and a symbiotic and/or hybrid system can be applied, which is introduced in the present study. On the other hand, in fusion reactor there are many parts having large temperature difference because plasma temperature is high and superconducting magnets are used. One of the applications for superconducting system is mentioned and is called Peltier current lead. This can reduce heat leak to low-temperature system, and improve the efficiency of the whole system. Recently, material study has progressed, and various kinds of materials are proposed and studied. The magnetic field effect is introduced as investigated by the author's research group. Magnetic field effect was divided into three levels of the categories. One is in the macroscopic level, and this is characterized by the generalized Ohm's equation. The second level is characterized by Boltzmann equation, and in this level we can discuss the macroscopic transport parameters. The third level is the microscopic level and we discuss the band structure to solve the carriers themselves, for example Schrödinger equation. In this paper, our recent activities are mentioned in these fields.

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Boltzmann-Gibbs statistical mechanics is known to exhibit fundamental difficulties when a system under consideration contains long-range interactions. Tsallis' nonextensive statistical mechanics offers a consistent theoretical framework for treatment of such a system. In this article, an approach to statistically describing pure-electron plasma based on the Tsallis entropy is reviewed and related problems are discussed.

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The design of electrostatic energy analyzer for charged particles is described in this paper. A program for potential calculation including space charge is used here. The results show that the energy distribution of charged particles can be obtained with good resolution (about 1%) by the combination of elliptical electrodes. This analyzer has a wide angular aperture, thus the high throughput is expected. Also, it can resolve the particleenergy; therefore it can be applied to the short pulse beam measurement like ion scattering spectroscopy (ISS). In conclusion, this analyzer described here will be one of hopeful energy distribution measurements of charged particles like Cylindrical Mirror Analysis (CMA).

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The study of wall recycling of long duration discharge has been carried out using 2.45 GHz and 8.2 GHz lower hybrid current drive in the superconducting tokamak TRIAM-1M. The recycling coefficient increases with two time constants. One is 1˜3 s and the other is ˜30 s. These two time constants are common to low (˜2 × 10¹⁸ m^-3) and high (˜1 × 10¹⁹ m^-3) density discharges. In the ultra-long discharge, the wall repeats a process of being saturated and refreshed. One possible candidate of the mechanism of wall refreshment is co-deposition of in vessel element (i.e. Molybdenum). In the high density discharge, the wall becomes saturated and the discharge is terminated due to the density increase. The achievable discharge duration becomes shorter as the plasma density is higher.

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From the year 2000 to 2001, the computer system located on Naka Fusion Research Establishment, Japan Atomic Energy Research Institute has been replaced. Since the main computer is the scalar parallel computer, which is about 40 times superior to the previous one, the amount of data outputted from the numerical simulations becomes much larger. In this paper, which scientific visual analysis system is more useful to extract the physical phenomena from such a large amount of data is investigated and the performance of the established visual analysis system is estimated.

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