The dependence of the backward wave oscillator's (BWO's) microwave output power on the number of corrugations is observed experimentally. The slow-wave structure (SWS) of the BWO has been designed to operate at 9.8 GHz . The SWS consists of detachable corrugated modules, and the corrugation number N can be changed from 1 up to 10. The BWO is driven by the high current electron accelerator LAX-1 (850 keV, 3 kA). The dependence of power on corrugation number is not monotonic; with 3 modules, a small output signal of 20kW level is observed; with 4 modules, a rapid increase of output power of the level of 10 MW is observed, and from 5 to 10 modules the output power appears to saturate at the power level of 100MW. These results are analyzed with a PIC Code called Magic.

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Stationary solitary electromagnetic waves generated in ultraintense relativistic laser-plasma interactions are studied numerically. For one-dimensional stationary propagation with circular polarization, subcycle solitary waves moving with finite velocity are obtained for a given value of wave velocity and nonlinear frequency shift, and it is shown that the solitary-wave amplitude increases for the larger nonlinear frequency shift. A new type of solitary-wave solution, a paired solution of positive and negative solitary waves, is also shown.

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There has been a long-standing discrepancy between the number of neutrinos expected from the sun and the number we actually detect. One possible way to account for this is that our theoretical solar model is inaccurate. However, recent progress in helioseismology has shown that the real sun is very close to the latest solar models. On the other hand, very recent experiments of neutrino detection provided us evidence for neutrino oscillation. I discuss what we should do and what we can do in this situation for the neutrino physics from the astrophysical side.

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Recent progress in electron Bernstein wave physics for electron cyclotron heating and electron cyclotron emission measurement in over-dense toroidal plasmas such as spherical tokamaks are reviewed. First, the theoretical bases of mode-conversion processes including X-B and O-X-B processes are described and discussed. Second, basic characteristics of electron Bernstein waves are described, and their propagation and absorption characteristics in toroidal plasmas including N_// up-shift are described and discussed. Finally, recent experimental studies and efforts are reviewed.

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The application of alkali-metal ion or atomic beams to the diagnostics of magnetically confined plasmas has a long history. Thermionic ion sources are used mostly because of their ease of handling. Fine probing beams and rather large atomic collision cross sections provide good spatial and temporal resolution of the measurements. Among the variety of this kind of diagnostics, two methods are reviewed as typical examples: a heavy ion beam probe (HIBP) and beam probe spectroscopy using a neutral lithium beam (LiBP).

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The heavy-ion inertial confinement fusion scenario requires high-power heavy-ion beams which can deposit energy of several MJ to small fuel targets during a short period of ˜ 10 ns. The space charge effect plays an important role in the intense beams of heavy ions. Various efforts are made to study the behaviors of the intense ion beams and to overcome the space charge effect. RF accelerators, which are used for various sciences, are further developed to deliver the beam pulses at more than kJ energy. USA and Japan have investigated induction accelerators because of their potential to drive the beams of current up to kA.

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Ion sources for the International Fusion Materials Irradiation Facility (IFMIF), an accelerator-based high intensity neutron source to test and develop materials for fusion machines, are developed. The required specifications of the ion source are 100 keV, and 155 mA of D⁺ with CW operation. This report presents an overview of the IFMIF and the current status of the ion source development.

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The beam technology developed for neutral beam injection in thermonuclear fusion research has been applied to industry. Currently, positive ion beams are widely applied to processing of semiconductors. For example, intense argon ion beams are used for milling substrates of silicon wafers, and large-area liquid crystal displays are also manufactured by implanting P⁺ or B⁺ ions on glass plates. Recently, intense negative ion beams have also been developed and are being applied to new fields in the semiconductor industry. Japan Atomic Energy Research Institute (JAERI) is developing a new technology to slice thin single-crystal semiconductor films of several tens of micrometers in thickness from the ingot without waste by implanting the MeV-class H^- ion beam developed for ITER. This process is realized only by utilizing the high-energy negative ion beam since positive ion implantation requires mass separation that practically limits the ion beam energy, namely, the penetration depth of the ions. By implanting 725 keV H^- ions directly onto the Si ingot, single-crystal Si plates of 10 µm in thickness have been successfully sliced. It is expected that this technology will allow the mass productions of high efficiency solar cells and micro-machines.

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More than 1,000 patients have been treated with carbon ions emerged from a medical synchrotron HIMAC. The treated patients had tumors in head and neck area, lung, liver, prostate, uterus, and other parts of body. Clinical studies show excellent results and the side effects are kept at extremely low levels. This paper describes a brief history of radiation therapy developed during the 20th Century, provides an outline of the theoretical background of radiation therapy, and shows the recent results of carbon therapy performed at National Institute of Radiological Sciences, NIRS. The paper describes other facilities for charged particle therapy developed in this country and in other parts of the world.

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The application of ion beam is reviewed from the standpoint of modeling for ”the interaction between ion beam and matters”. The theory and basic Monte-Carlo simulation codes for end-users are explained first with some advice for customization. Molecular Dynamic (MD) simulation is recommended to depict the relaxation process following ion irradiation, both for living and non-living systems. Since the space-time of MD simulation is rather narrow, one can expand it by hybridizing MD with other computation codes. In principle, the fewer the missing-rings by piling up experimental data, the better computation model we can make. However, in order to model a complex system, a break-through is required.

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Electron-positron plasmas are believed to exist around the center of galaxy and compact stars. This relativistic electron-positron pair plasma has special features different from normal plasmas. The equilibrium conditions are given to solve the rate equation for pair creations and pair annihilation. The limit of temperature exists around 15 MeV under the condition that electron-positron plasma stays in equilibrium. In addition to the astrophysical plasmas, the dense electron-positron plasmas are produced by ultra-intense lasers in alaboratory.The studies of the relativistic electron-positron plasmas become important subjects in both astrophysics and laboratory plasma physics.

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Relativistic flows have been observed in jets and gamma-ray bursts. Such phenomena are not fully understood. In order to study such flows, we need to consider relativistic effects. In this paper, we first explain relativistic hydrodynamic equations. Some characteristics relativistic flows are discussed, namely, the adiabatic exponent and sound speed for high temperature fluid, and shock jump conditions. Second, we show relativistic jets as an example of relativistic flows. Observations of jets and theoretical models for acceleration, collimation, and propagation of jets are given.

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The structure of the electric field is studied by use of the theoretical model for the anomalous transport diffusivities. In this analysis, the thermal diffusivity is employed based on the theory of self-sustained turbulence due to the balooning mode and the interchange mode, both driven by the current diffusivity. Multiple solutions of E_r for the ambipolar condition are obtained in the structure of the radial electric field. The reduction of the anomalous transport coeffient is examined due to the strong gradient of the radial electric field in the phase diagram of the external sources.

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In GAMMA 10, the plasma potential at the plug region, which is generated by fundamental ECRH, is linked to the end plate potential. There are two factors in this linkage. One is the field-aligned flow of warm electrons driven into the loss cone by ECRH. The other is a finite current through the end plate. This current is connected to an ion current, which is detected on annular electrodes in the end mirror cell where the plug potential is formed. An experimental attempt to externally control this current was performed by varying the resistance connecting the end plate to the vacuum vessel, and a picture of current circulation was obtained. In this circuit, ECRH generates an electromotive force by driving the axial flow of electrons. This electromotive force is divided into the positive plug potential and the negative end plate potential, respectively as measured from the vacuum vessel to meet the condition of a closed circuit.

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