A5006106430- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Nuclear reactor physics and engineering
- Fusion materials and technologies
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Advanced Data Compression Techniques
- Laser-Plasma Interactions and Diagnostics
- Video Coding and Compression Technologies
- Radiation Therapy and Dosimetry
- Photocathodes and Microchannel Plates
- Ionosphere and magnetosphere dynamics
- Embedded Systems Design Techniques
- Digital Filter Design and Implementation
- Nuclear physics research studies
- Diamond and Carbon-based Materials Research
- Graphite, nuclear technology, radiation studies
- High-pressure geophysics and materials
- Advanced Vision and Imaging
- Glass properties and applications
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
Nagoya University
2003-2024
National Institute for Fusion Science
1990-2021
National Institutes of Natural Sciences
2017-2021
Kyushu University
2021
The Graduate University for Advanced Studies, SOKENDAI
2014-2018
Korea Institute of Fusion Energy
2018
Seoul National University
2018
Osaka University
2018
Japan Atomic Energy Agency
2006-2015
Toshiba (Japan)
2014
In order to support the operation of ITER and planned experimental programme an extensive set plasma first wall measurements will be required. The number type required similar those made on present-day large tokamaks while specification measurements—time spatial resolutions, etc—will in some cases more stringent. Many used real time control driving a requirement for very high reliability systems (diagnostics) that provide measurements.
A folded architecture and a digit-serial are proposed for implementation of one- two-dimensional discrete wavelet transforms. In the one-dimensional architecture, computations all levels to same low-pass high-pass filters. The number registers in is minimized by use generalized life time analysis. converter units synthesized with minimum using forward-backward allocation. advantage low latency its drawbacks increased hardware area, less than 100% utilization, complex routing interconnection...
Spontaneous formation of an internal transport barrier was observed associated with improved confinement in the high-${\mathrm{\ensuremath{\beta}}}_{\mathit{p}}$ discharges JT-60U tokamak. The radial location found to be on q=3 surface. A fast magnetohydrodynamic event localized at triggered subsequent edge that resulted further improvement. In these discharges, a high poloidal rotation velocity significantly exceeded prediction present neoclassical theory also r/a=0.8.
The design progress in a compact low aspect ratio (low A ) DEMO reactor, ‘SlimCS’, and its issues are reported. study focused mainly on the torus configuration including blanket, divertor, materials maintenance scheme. For continuity with Japanese ITER-TBM, blanket is based water-cooled solid breeder blanket. vertical stability of elongated plasma high beta access, segmented into replaceable permanent blankets sector-wide conducting shell arranged inbetween these blankets. numerical...
Recent results on investigations of Alfvén eigenmodes, fast ion confinement and diagnostics in JT-60U are presented. It was found that toroidicity induced eigenmodes (TAEs) were stable negative shear discharges with a large density gradient at the internal transport barrier (ITB). If small ITB, multiple TAEs appeared around q = 2 surface (pitch minimum) showed frequency chirping (Δf ≈ 80 kHz). In low-q positive discharges, location changed from outside to inside 1 surface, owing temporal...
Peak fusion power production of 6.2\ifmmode\pm\else\textpm\fi{}0.4 MW has been achieved in TFTR plasmas heated by deuterium and tritium neutral beams at a total 29.5 MW. These have an inferred central alpha particle density 1.2\ifmmode\times\else\texttimes\fi{}${10}^{17}$ ${\mathrm{m}}^{\mathrm{\ensuremath{-}}3}$ without the appearance either disruptive magnetohydrodynamics events or detectable changes Alfv\'en wave activity. The measured loss rate energetic particles agreed with...
The deuterium operation of the large helical device (LHD) began in March 7, 2017, after long-term preparation and commissioning apparatuses necessary for execution experiment. A comprehensive set neutron diagnostics was developed installed onto LHD through numerous efforts preparation. Neutron play an essential role both yield management radiation safety extension energetic-particle physics study LHD. flux monitor (NFM) characterized by fast-response wide dynamic range capabilities is...
The concept for a compact DEMO reactor named 'SlimCS' is presented. Distinctive features of the are low aspect ratio (A = 2.6) and use reduced-size centre solenoid (CS) which has function plasma shaping rather than poloidal flux supply. CS enables us to introduce thin toroidal field coil system contributes reducing weight perhaps lessening construction cost. Low-A merits vertical stability high elongation (κ) normalized beta (βN), leads power density with reasonable physics requirements....
A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ∼5 × 109 counts/s. Because a total emission over 1 1016 n/s is predicted in neutral beam-heated plasmas, response and capabilities of system are essential. Preliminary tests have demonstrated successful performance as along design.
Understanding of energetic particle (EP) confinement is one the critical issues in realizing fusion reactor.In stellarator/helical devices, research on EP key topics to obtain better by utilizing flexibility three-dimensional magnetic field.Study transport Large Helical Device (LHD) has been performed means escaping diagnostics hydrogen plasma operation.By starting deuterium operation LHD, study EPs progressed remarkably using newly developed comprehensive neutron providing information...
The deuterium operation of the Large Helical Device (LHD) heliotron started in March 7, 2017, after longterm preparation and commissioning works necessary to execute experiment.A comprehensive set neutron diagnostics was implemented accelerate energetic-particle physics research LHD.The calibrated ex-vessel flux monitor indicated that total emission rate first campaign reached 3.3×10 15 n/s inward shifted magnetic field configuration where confinement helically trapped energetic ions is...
Instabilities with frequency chirping in the range of Alfvén eigenmodes have been found domain 0.1% < ⟨βh⟩ 1% and vb||/vA ∼1 high energy neutral beam injection JT-60U. One instability a inside continuum spectrum appears its increases slowly to toroidicity induced eigenmode (TAE) gap on timescale an equilibrium change ( ≈ 200 ms). Other instabilities appear TAE their frequencies very quickly by 10-20 kHz 1-5 ms. During period when these fast sweeping (fast FS) modes occur, abrupt large...
Fusion performance of reversed shear discharges with an L-mode edge has been significantly improved in a thermonuclear dominant regime up to 2.8 MA plasma current the JT-60U tokamak. The core energy is efficiently confined due existence persistent internal transport barriers formed for both ions and electrons at large minor radius $r/a\ensuremath{\sim}0.7$ near boundary region. In assumed deuterium-tritium fuel, peak fusion amplification factor defined transient conditions involving $dW/dt$...
The Tomamak Fusion Test reactor has performed initial high-power experiments with the plasma fueled nominally equal densities of deuterium and tritium. Compared to pure plasmas, energy stored in electron ions increased by \ensuremath{\sim}20%. These increases indicate improvements confinement associated use tritium possibly heating electrons \ensuremath{\alpha} particles created D-T fusion reactions.
This paper describes large-scale-integration programmable processors designed for multimedia processing such as real-time compression and decompression of audio video well the generation computer graphics. As target these is to handle in real time, capability must be increased tenfold compared that conventional microprocessors, which were mainly texts, figures, tables, photographs. To clarify advantages a high-speed capability, we define chips processors. General-purpose microprocessors...
Absolutely calibrated measurements of the neutron yield are important for evaluation plasma performance such as fusion gain Q in D–D operating tokamaks. The time-resolved is measured with 235U and 238U fission chambers 3He proportional counters JT-60U tokamak. situ calibration was performed by moving 252Cf source toroidally through JT-60 vacuum vessel. Detection efficiencies three two detectors were 92 locations point toroidal scans at different major radii. total detection efficiency torus...
GaAs–GaAsP and InGaAs–AlGaAs strained-layer superlattice photocathodes are presented as emission sources for highly polarized electron beams. The cathode achieved a maximum polarization of 92(±6)% with quantum efficiency 0.5%, while the provides higher (0.7%) but lower [77(±5)%]. Criteria achieving high using discussed based on experimental spin-resolved spectra.
Experiments have been carried out in JT-60U to verify the modelling of fast ion ripple transport. The induced loss was estimated from neutron decay following neutral beam pulse injection and related heat load on first wall. Comparison lost fraction hot spot positions between measurements orbit Monte Carlo calculations exhibited good agreement, indicating that transport governing losses is explained within framework existing theory. Neutral heating experiments also indicate H modes free ELMs...
Due to the high neutron yield and large plasma size many ITER parameters such as fusion power, power density, ion temperature, fast energy their spatial distributions in core can be measured well by various diagnostics. Neutron diagnostic systems under consideration development for include radial vertical cameras (RNC VNC), internal external flux monitors (NFMs), activation spectrometers. The two-dimensional source strength spectral measurements provided combined RNC VNC. NFMs need meet...
The H mode was achieved in limiter discharges of a tokamak with lower-hybrid current drive for the first time. Simultaneous application rf powers at two different frequencies such as 1.74 and 2.23 GHz or 2.0 appeared to be effective attainment mode. threshold power low Ohmic-heating hydrogen plasmas. A nearly steady-state edge-localized-mode-free duration up 3.3 sec established without significant impurity accumulation.
In the currently performed neutral beam (NB) -heated deuterium plasma experiments, neutrons are mainly produced by a beam-plasma reaction. Therefore, time-resolved measurement of neutron emission profile can enhance understanding classical and/or anomalous transport ions. To measure radial profiles as function time, vertical camera (VNC) capable operation with counting rate in MHz range was newly installed on Large Helical Device (LHD). This is world's first for stellarator/heliotron...