A novel plasma source of atmospheric-pressure glow (APG) discharge in contact with solution is developed. Liquid paraffin consisting of hydrocarbons is used as solution for the purpose of the formation of carbon nanotubes at the gas-liquid interface, i.e., the boundary between glow discharge (gas-phase) and solution (liquid-phase) layers. We have succeeded in generating a stable APG discharge plasma in contact with liquid paraffin by using a capacitively coupled plasma method with mesh electrode.

View full abstract

This paper is devoted to numerical study of the location of the imaging optics object plane. The simulation shows that in the case of the plane plasma cutoff, the object plane is located at the virtual cutoff position defined by E. Mazzucato [Nuclear Fusion 45, 203 (2001)], while in the case of cylindrical plasma, the object plane is shifted toward the cutoff position.

View full abstract

Beam ion loss due to the charge exchange with deuterium atoms in the open field region of a field-reversed configuration (FRC) is investigated by tracing its orbit. The beam ion is tangentially injected as neutral beams (NBs) into the FRC. The ionization process is reproduced by the Monte-Carlo method. Almost all of the 15 keV beam ions injected toward the field null are found to be confined in the case with an external magnetic field of 0.2 T. It is found that about 90% of the NB injection power is transferred to the plasma when the neutral atom density in the open field region is lower than 10¹⁷ m^-3.

View full abstract

In the extremely low density plasmas in the Universe, the energy distribution of electrons starts to deviate from Maxwellian distribution, when acceleration processes, such as the Fermi acceleration process are operative with a magnetic field moving at high velocity. Radiation from these electrons is expected in the X-ray wave band by synchrotron radiation and by inverse-Compton scattering. Supernova remnants and clusters of galaxies exhibit thermal emission from hot plasmas of several keV as well as non-thermal power law components above 20 keV, which suggests that the acceleration process takes place. A new hard X-ray imaging telescope system is also presented.

View full abstract

As one of the engineering test programs in ITER, the test blanket program, which utilizes ITER as a test bed to develop breeding blanket systems for fusion DEMO plants, has been planned and advanced. The Test Blanket Working Group (TBWG) has been organized to review and coordinate test programs on Test Blanket Modules(TBM). Five breeding blanket concepts have been proposed and discussed in the TBWG, and Japan is participating in the development of all of these concepts. This paper describes the status of TBM design, blanket technology and materials development for ITER TBMs. The current design and R&D status of candidate TBM concepts, which include 1) a water-cooling system with a solid breeder, 2) a helium gas-cooling system with a solid breeder, 3) a lithium-lead (LiPb) breeding system, 4) a liquid lithium breeding system, and 5) a molten salt breeding system, are presented and discussed.

View full abstract

Mach probe with two collecting tips facing to the direction parallel and perpendicular to the plasma flow, named para-perp type one, is evaluated by using a directional Langmuir probe (DLP) in a fast owing plasma produced by an MPD (Magneto-Plasma-Dynamic) arcjet. We present simple formulas to determine an ion acoustic Mach number M_i from the ratio of collected ion saturation currents. The formulas and experimentally-obtained data are compared with Hutchinson’s simulation results which are calculated using a particle-in-cell(PIC) code in an unmagnetized plasma condition. [I.H. Hutchinson, Plasma Phys. Control. Fusion, 44 1953 (2002).] Good agreements are obtained among these data in both subsonic and supersonic plasma flows. Correction factor κ to determine M_i is presented under various conditions of T_i/T_e and the specific heat ratio for ions γ_i.

View full abstract