A5028551898- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Semiconductor materials and devices
- Semiconductor Lasers and Optical Devices
- Radiation Detection and Scintillator Technologies
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Solar Radiation and Photovoltaics
- Advanced materials and composites
- Advanced Fiber Optic Sensors
- Urban Heat Island Mitigation
- Photonic and Optical Devices
- Nuclear reactor physics and engineering
- Remote Sensing in Agriculture
- TiO2 Photocatalysis and Solar Cells
- Plasma Diagnostics and Applications
- Magneto-Optical Properties and Applications
- Advanced Fiber Laser Technologies
Toyohashi University of Technology
2022-2024
Kansai University
2018-2022
National Institutes for Quantum Science and Technology
2018-2021
The Graduate University for Advanced Studies, SOKENDAI
2015-2019
Tokyo University of Agriculture and Technology
2014
Hiroshima University
2010
The University of Tokyo
2004-2005
As the finalization of a hydrogen experiment towards deuterium phase, exploration best performance plasma was intensively performed in large helical device. High ion and electron temperatures, Ti Te, more than 6 keV were simultaneously achieved by superimposing high-power cyclotron resonance heating onneutral beam injection (NBI) heated plasma. Although flattening temperature profile core region observed during discharges, one could avoid degradation increasing density. Another key parameter...
The deuterium (D) operation was initiated in the LHD 2017. In first campaign of D experiments, we successfully extended high temperature regime LHD. new record ion (Ti) 10 keV associated with internal transport barrier (ITB) achieved due to several operational optimization. thermal confinement characteristics ITB plasmas were compared between hydrogen and discharges. effective diffusivity ion-ITB found be smaller discharges than that H profiles Ti, electron density, impurity Ti strongly...
The resistive interchange mode destabilized by the resonant interaction with trapped energetic ions is fully suppressed when injected power of electron cyclotron heating exceeds a certain threshold. It shown for first time that complete stabilization energetic-particle-driven without relaxing particle (EP) pressure gradient possible reducing radial width eigenmodes ${\ensuremath{\delta}}_{w}$, especially ${\ensuremath{\delta}}_{w}$ narrows to small enough value relative finite orbit EP.
Energetic ion driven resistive InterChange modes (EICs) accompanying repeated bursts of the magnetic fluctuations were found in hydrogen campaign large helical device. The pressure gradient helically trapped energetic particles, which are mainly produced by perpendicularly injected beams, drives this mode. Recently, perpendicular neutral beam injection (PERP-NBI) systems upgraded for deuterium plasma campaign. energies two PERP-NBIs increased from 40/40 keV to 60/80 keV, respectively. And...
A remarkable extension of the high-ion-temperature (high-Ti) regime was obtained in deuterium plasma experiments Large Helical Device. In order to clarify transport characteristics ion internal barrier (ITB) formation with an isotope effect, a dataset pure (nD/ne > 0.8) and hydrogen (nH/ne plasmas high-Ti were analyzed, two mechanisms improvement characterized. significant reduction heat core both observed, indicating ITB formation. The dependence diffusivity on temperature ratio (Te/Ti)...
Abstract Turbulent transport is undoubtedly important in magnetic confinement plasmas. It has been reported that a lot of dynamics are not satisfying the local diffusive models. Here, we report quantitative measurement electron heat flux associated with ballistic propagating long-range events, which considered to be component avalanches. In addition, show first observations substantial impact avalanche-driven on profile resilience (or stiffness) observed JT-60U. We found that, channel flux,...
Abstract The avalanche type of transport can induce a long-radial and thus contribute to the global profile formation. In this study, we observed heat perturbations exhibiting avalanche-like in stellarator/heliotron device, Heliotron J, tokamak JT-60U. We found that electron propagation J is mainly generated from heating source region. relatively high value Hurst exponent, which signature avalanches, depends on total power. On other hand, ion avalanches measured JT-60U tend spread local peak...
Abstract Diamond-like carbon (DLC) films with excellent mechanical properties are used as functional surface protective for cutting tools. The deposition rate of DLC using conventional plasma chemical vapor (CVD) methods is several hundred nm min −1 . This study applied a negative DC pulsed voltage to substrate stage irradiated an Ar/C 2 H mixed jet. effect the on fabricated was investigated based thicknesses and characteristics films. were formed Si substrates jet CVD system. Ar ejected...
Abstract Emissions of ion-cyclotron-range-of-frequency (ICRF) waves have been observed in a solely electron-cyclotron-resonance-heated plasma, namely no fast-ion on the JT-60U tokamak for first time. The mode frequencies are around ion cyclotron frequency at low-field-side plasma edge. considered to be electromagnetic and standing from poloidal toroidal phase differences measured with ICRF antennas. Wave characteristics emissions such as frequency, polarization propagation similar those...
Several solar irradiation forecasting methods are being developed toward economically efficient power generation. Among these, the method that utilizes all sky imagers to estimate direction of cloud movement above certain observation points is able forecast fluctuations in with localized temporal resolution (∼30 min) through shadows cast by clouds. The one-layered usually assumed movement. However, reality, multilayered clouds may move different directions sky. While such have effect on...
In magnetic fusion plasmas, a transport barrier is essential to improve the plasma confinement. The key physics behind formation of suppression micro-scale turbulent transport. On other hand, long-range events, such as avalanches, has been recognized play significant roles for global profile formations. this study, we observed impact avalanche-type on first time. avalanches are found inhibit internal (ITB) in JT-60U tokamak. We that (1) ITBs do not form presence but under disappearance (2)...
Multi-channel soft x-ray (SX) diagnostic has been used in the large helical device (LHD) to research magnetohydrodynamic equilibria and activities. However, coming deuterium plasma experiments of LHD, it will be difficult use semiconductor systems near LHD. Therefore, a new type SX diagnostic, scintillator-based investigated order avoid damage from radiation. A fiber optic plate coated by P47 scintillator detect emission. Scintillation light transferred pure silica core optical fibers...
Two types of oscillation phenomena are found just after hydrogen ice pellet injections in the Large Helical Device (LHD). Oscillation appear when deposition profile a is localized around rotational transform ι = 1 rational surface. At first, damping oscillations (type-I) only soft X-ray (SX) emission. They followed by second type (type-II) where magnetic fluctuations and density synchronized to SX observed. Both have poloidal/toroidal mode number, m/n 1/1. Since type-II local pressure large...
In JT-60U, simultaneous excitation of n = 1 helical cores (HCs) and m/n 2/1 Tearing Modes (TMs) was observed [T. Bando et al., Plasma Phys. Control. Fusion 61 115014 (2019)]. this paper, we have investigated the mechanism HCs with TMs based on experimental observations a simple quasi-linear MHD model. previous study, it reported that "coupling" phase mode is between TMs. found coupling frequency from several Hz to 6 kHz. This indicates resistive wall plasma control system do not induce...
Abstract The effects of the stochastic magnetic field in a plasma center produced by electron cyclotron current drive (ECCD) on transport have been revealed. Because temperature profile is flat core region, case counter-directed ECCD (ctr-ECCD) against toroidal field, region with rotational transform ᵼ ∼ 1/3. particle diffusion coefficient ctr-ECCD approximately 20 times as large that without co-directed (co-ECCD) at maximum. Furthermore, ctr-ECCD, intrinsic rotation observed balanced NBI discharge.
In the Large Helical Device (LHD) semiconductor-based detector arrays for soft X-ray (SX) emission have been used studying MHD instabilities.However, a semiconductor device is expected to be damaged in high neutron flux environments coming LHD deuterium plasma experiments.In order measure an SX such environments, CsI:Tl scintillator-based diagnostic being developed.Though sensitive and gamma-ray, as well, effects on scintillation light can reduced if very thin foil (50 micrometers) used.An...
The thin gap chambers (TGCs) are used for the muon trigger system in end-cap regions of ATLAS detector. TGC mass production phase at High Energy Accelerator Research Organization (KEK) started January 2001. As anode-cathode distance is small, 1.4 mm, chamber flatness essential to achieve a uniform gas gain over chamber. In order perform stable with high quality we developed closing system. When glue two half-chambers together, sandwich them between granite table and an aluminum honeycomb...
Thin gap chamber modules giving function of forward muon trigger to the ATLAS detector in LHC experiment have been constructed at High Energy Research Organization (KEK) Japan and their performances checked Kobe University. A large-scale test system specially designed for measuring uniformity detection efficiencies timing resolution 8 TGC same time was successfully operated. Each module had 72 anode wire channels 64 cathode strip (in total 1088 readout modules). Drift tubes consisted 12...