M. Kobayashi
A5050075379- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle physics theoretical and experimental studies
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Dark Matter and Cosmic Phenomena
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Semiconductor Quantum Structures and Devices
- Physics of Superconductivity and Magnetism
- Atomic and Molecular Physics
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Neutrino Physics Research
National Institute for Fusion Science
2015-2024
The Graduate University for Advanced Studies, SOKENDAI
2015-2024
National Institutes of Natural Sciences
2013-2024
Nagoya University
1983-2022
Chiba Institute of Technology
2014-2022
Heinrich Heine University Düsseldorf
2022
Osaka Institute of Technology
2022
Tokyo Metropolitan University
1989-2020
Nagaoka University of Technology
2020
Fusion Academy
2012-2019
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...
Abstract The EMC3‐Eirene code is improved in many aspects. Ad hoc boundary conditions for intrinsic impurities at the SOL‐core interface are removed by implicitly coupling to a 1D core model. Non‐uniform cross‐field transport coefficients allowed new version. A particle splitting technique implemented improving Monte Carlo statistic low‐temperature ranges of most interest. Domain splitting, which was possible toroidal direction only, now feasible all three directions, facilitating mesh...
Abstract Since the publication of review Progress in ITER Physics Basis (PIPB) 2007, significant progress has been made understanding processes at plasma-material interface. This review, part ITPA Nuclear Fusion Special Issue On Path to Burning Plasma Operation , presents these developments, focusing on key areas such as physics plasma exhaust, interactions, and properties plasma-facing materials their evolution under exposure. The coordinated efforts Topical Group Scrape-Off Layer Divertor...
In reduced recycling discharges in the Large Helical Device, a super dense core plasma develops when series of pellets are injected. A region with density as high 4.5 x 10(20) m(-3) and temperature 0.85 keV is maintained by an internal diffusion barrier very high-density gradient. These results may extrapolate to scenario for fusion ignition at relatively low helical devices.
We present magnetization (M) and magnetoresistance (MR) data for a series of Sr2FeMoO6 samples with independent control on antisite defect grain-boundary densities, which reveal several unexpected features, including novel switching-like behavior MR M. These, in conjunction model calculations, establish that the is dominantly controlled by new mechanism, derived from magnetic polarization regions acting like spin valves, leading to qualitatively different usually encountered tunneling MR....
This paper compares the essential divertor transport features of poloidal divertor, which is well developed for tokamaks, and non-axisymmetric divertors currently investigated on helical devices. It aims at surveying fundamental similarities differences in concept geometry, their consequences functioning a divertor. In particular, importance various terms governing axisymmetric scrape-off layers (SOLs) examined, with special attention being paid to energy, momentum impurity transport....
The goal of the DIRAC experiment at CERN (PS212) is to measure $\pi^+\pi^-$ atom lifetime with 10% precision. Such a measurement would yield precision 5% on value $S$-wave $\pi\pi$ scattering lengths combination $|a_0-a_2|$. Based part collected data we present first result lifetime, $\tau=[2.91 ^{+0.49}_{-0.62}]\times 10^{-15}$ s, and discuss major systematic errors. This corresponds $|a_0-a_2|=0.264 ^{+0.033}_{-0.020} m_{\pi}^{-1}$.
This paper presents results of statistical analysis RTN in highly scaled HKMG FETs. A robust algorithm to extract multiple-trap is proposed and applied show that can cause serious variation even when undoped channel are introduced. We further focus on hysteretic behavior caused by with time constants much longer than the circuit timescale. reveals also induces novel instabilities such as short-term BTI logic delay uncertainty. Extraction SRAM arrays presented discuss its impact operational stability.
It is found that resonant magnetic perturbation (RMP) fields have a stabilizing effect on the radiating edge plasma, realizing stable sustainment of radiative divertor (RD) operation in Large Helical Device (LHD). Without RMP, thermal instability leads to collapse. Divertor power load reduced by factor 3–10 during RMP-assisted RD phase, while maintaining relatively good core plasma confinement with enhancement . has also been demonstrated RMP field itself can initiate transition increasing...
The Wendelstein 7-X (W7-X) optimized stellarator fusion experiment, which went into operation in 2015, has been operating since 2017 with an un-cooled modular graphite divertor. This allowed first divertor physics studies to be performed at pulse energies up 80 MJ, as opposed 4 MJ the phase, where five inboard limiters were installed instead of a This, and number other upgrades device capabilities, extension regimes higher plasma density, heating power, performance overall, e.g. setting new...
Abstract In recent deuterium experiments on the large helical device (LHD), we succeeded in expanding temperature domain to higher regions for both electron and ion temperatures. Suppression of energetic particle driven resistive interchange mode (EIC) by a moderate increase is key technique extend high LHD plasmas. We found clear isotope effect formation internal transport barrier A new measure hydrogen fraction was developed order investigate behavior mixing state. The revealed that...
In this work we investigate the two-neutron decay of 13Li and excited states 11Li populated via one-proton removal from 14Be 12Be, respectively. A phenomenological model is used to describe 13Li. While first one displays important sequential components, second appears dominated by direct decay. microscopic three-body extract information on spatial configuration emitted neutrons before shows that average distance between increases going
Abstract This paper describes the implicit integration and consistent tangent modulus of an inelastic constitutive model with transient steady strain rates, both which are time‐ temperature‐dependent; rate is influenced by evolution back stress decomposed into parts, while depends only on applied temperature. Such a non‐unified useful for high‐temperature structural analysis practical owing to ease in determining material constants. The shown result two scalar‐valued coupled equations,...
We demonstrated SONOS flash memory with a SiO/sub 2//High-k/SiO/sub 2/ structure based on 2-bit/cell scheme. evaluated three kinds of high-k dielectric films which were Si/sub 3/N/sub 4/, Al/sub 2/O/sub 3/ and HfO/sub 2/. Among these films, showed superior retention characteristics. The charge loss amount at 150/spl deg/C is almost the same as that 4/ 25/spl deg/C. poor In addition, we have found each film has different mechanism. speculate causes vertical migration, scarcely any leakage,...
The Large Helical Device (LHD) and Wendelstein 7-X (W7-X, under construction) are experiments specially designed to demonstrate long-pulse (quasi steady state) operation, which is an intrinsic property of stellarators heliotrons. Significant progress has been made in establishing high performance plasmas. A crucial point the increasing impurity confinement at density observed several machines (TJ-II, W7-AS, LHD) can lead accumulation early pulse termination by radiation collapse. In...
Abstract An extended mesh system for EMC3‐EIRENE has been developed to simulate peripheral plasma including the ergodic and divertor leg regions of LHD. Both open closed configurations are available. A series simulations 8MW input power, five different electron densities at LCFS (last flux surface) open/closed were carried out. Approximately 10 times larger neutral pressure was observed under dome structure compared with configuration, which is in good agreement experimental measurements. In...
Modeling of impurity-seeded plasma in Large Helical Device (LHD) is presented for the first time by using three-dimensional transport code EMC3-EIRENE.High and low recycling coefficients impurity ions are assumed to include high absorption rates on wall surfaces due chemical activity neon nitrogen, respectively.Radiation power measured two bolometer systems particle flux divertor probes installed multiple toroidal sections utilized determine amount plasma.The uniformity non-uniformity a...
Abstract The transport properties and line emissions of carbon impurity in the stochastic layer Large Helical Device have been investigated with 3D edge code EMC3-EIRENE. A parameter study has performed to examine sensitivity simulation results on each term model source characteristics, i.e. amount location. modelling revealed that order reproduce experimental emission distribution, perpendicular coefficient ( D imp ) first wall play important roles, while changes ion thermal friction forces...
Abstract Recently, experiments on basic plasma physics issues for solving future problems in fusion energy have been performed a Large Helical Device. There are several to be solved devices energy. Emerging burning are: alpha-channeling (ion heating by alpha particles), turbulence and transport electron dominant helium ash exhaust, reduction of the divertor heat load. To solve these problems, understanding (1) wave–particle interaction through (inverse) Landau damping, (2) characteristics...
A variety of electron density (ne) profiles have been observed in the Large Helical Device (LHD). The change dramatically with heating power and toroidal magnetic field (Bt). particle transport coefficients, i.e. diffusion coefficient (D) convection velocity (V) are experimentally obtained standard configuration from modulation experiments. values D V estimated separately core edge. coefficients found to be a function temperature (Te), vary Bt. Edge proportional . Non-zero is observed, it...
It is found that the remnant island structure created by n/m=1/1 resonant magnetic perturbation field in stochastic boundary of Large Helical Device (LHD) [A. Komori et al., Nucl. Fusion 49, 104015 (2009)] has a stabilizing effect on formation radiating plasma, realizing stably sustained divertor detachment operation with core plasma being unaffected. The data from several diagnostics, (profiles electron temperature and density, radiation temporal evolution particle flux) indicate selective...
Remarkable progress in the physical parameters of net-current free plasmas has been made Large Helical Device (LHD) since last Fusion Energy Conference Chengdu, 2006 (Motojima et al 2007 Nucl. 47 S668 ). The beta value reached 5% and a high-beta state beyond 4.5% from diamagnetic measurement maintained for longer than 100 times energy confinement time. density temperature regimes have also extended. central exceeded 1 × 10 21 m −3 due to formation an internal diffusion barrier . ion 5.2 keV...