A5090653136- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Dust and Plasma Wave Phenomena
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- Laser-induced spectroscopy and plasma
- High-Energy Particle Collisions Research
- Earthquake Detection and Analysis
- Nuclear Materials and Properties
- Gas Dynamics and Kinetic Theory
- Particle Dynamics in Fluid Flows
- Quantum chaos and dynamical systems
- Vacuum and Plasma Arcs
- Atomic and Subatomic Physics Research
- Fluid Dynamics and Turbulent Flows
- Ion-surface interactions and analysis
- Cold Atom Physics and Bose-Einstein Condensates
- Evacuation and Crowd Dynamics
Osaka University
2014-2024
Japan Atomic Energy Agency
2003-2012
Taras Shevchenko National University of Kyiv
2006
Advanced Science Research Center
1995-2004
National Institute for Fusion Science
2004
Max Planck Institute for Plasma Physics
1996-2002
General Atomics (United States)
2000
Kurchatov Institute
1996-1998
Keio University
1997
Joint European Torus
1994
The understanding and predictive capability of transport physics plasma confinement is reviewed from the perspective achieving reactor-scale burning plasmas in ITER tokamak, for both core edge regions. Very considerable progress has been made understanding, controlling predicting tokamak across a wide variety conditions regimes since publication Physics Basis (IPB) document (1999 Nucl. Fusion 39 2137–2664). Major areas considered here follow. (1) Substantial improvement content, reliability...
On the basis of an analysis ITER L-mode energy confinement database, two new scaling expressions for tokamak are proposed, namely a power law and offset-linear scaling. The indicates that present multiplicity time τE in tokamaks (Goldston, Kaye, Odajima-Shimomura, Rebut-Lallia, etc.) is due both to lack variation key parameter combination fs = 0.32 R a−0.75 k0.5 ∼ A a0.25k0.5, variations dependence on physical parameters among different database. By combining multiples another factor, fq...
The input power requirements for accessing H-mode at low density and maintaining it during the ramp in ITER is addressed by statistical means applied to international threshold database. Following recent addition of new data, improvement existing data selection criteria, a revised scaling law that describes required obtain an L-mode transition presented. Predictions give ∼52MW deuterium plasma line average density, ne = 0.5×1020m-3. At nominal 1.0×1020m-3, ∼86MW. Detailed analysis from...
In JT-60U H-mode plasmas, giant (type I) ELMs disappear and minute grassy appear when triangularity δ, edge safety factor q95 βp are high enough. Complete suppression of was observed at δ≳0.45, q95≳6 βp≳1.6. At higher δ (0.54), can a lower (~4.0). the ELMy H-mode, temperature pressure be than those in favourable confinement sustained without an increase impurity concentration. An stability analysis suggests that plasma is accessing second regime n ballooning mode discharges.
The characteristics of internal transport barrier (ITB) structures are studied and active ITB control has been developed in JT-60U reversed shear plasmas. following results found. Outward propagation ITBs with steep Ti gradients is limited to the minimum safety factor location ρqmin. However, reduced can move outside lower boundary width proportional ion poloidal gyroradius at centre. Furthermore, strength based on modification radial electric field profile successfully demonstrated by...
The ITER Threshold Database, which at present comprises data from nine divertor tokamaks, is described. main results are presented and discussed. properties dependences of the power threshold in individual devices reviewed. In particular, analysis shows a rather general linear dependence on magnetic field, but non-monotonic density that varies device to device. Investigation combined database suggests P thres approximately=0.3n e B T 2.5 reasonable agreement with data. This expression yields...
We study a nonlinear effect on ion motion of an electrostatic wave propagating perpendicularly to uniform magnetic field. When the near cyclotron harmonics has sufficiently large amplitude, trapped motions hot ions (${v}_{\ensuremath{\perp}}>\frac{\ensuremath{\omega}}{{k}_{\ensuremath{\perp}}}$) become stochastic in region appreciable width separatrix. Numerical calculations show tail formation ${v}_{1}$ distribution and theoretically predicted upper bound conditioned by amplitude.
The paper discusses edge stability, beta limits and power handling issues for negative triangularity tokamaks. magnetohydrodynamic stability is the most crucial item handling. For case of picture quite different from that conventional positive tokamaks: second access closed localized Mercier/ballooning modes due to absence a magnetic well, nearly internal kink set pedestal height limit be weakly sensitive diamagnetic stabilization just above margin mode Mercier criterion violation. While...
The negative triangularity tokamak (NTT) is a unique reactor concept based on 'power-handling-first' philosophy with the heat exhaust problem as leading concern. present paper exposes using L-mode edge NTT configuration, providing merits of no (or very weak) edge-localized modes, larger particle flux and large major radius for power handling. It shown that reasonably compact (Rp from 9 m to 7 m) possible by achieving higher confinement improvement (HH = 1.5) and/or utilizing magnetic field...
This paper describes an update of the H mode confinement database that has been assembled for ITER project. Data were collected from six machines different sizes and shapes: ASDEX, DIII-D, JET, JFT-2M, PBX-M PDX. The updated contains better estimates fast ion energy content thermal times, discharges with RF heating, data using boronization, beryllium pellets, more systematic parameter scans, other features. list variables in expanded, selection criteria standard dataset have modified. We...
Describes the content of an H-mode confinement database that has been assembled for ITER project. Data were collected from six machines different sizes and shapes: ASDEX, DIII-D, JET, JFT-2M, PBX-M PDX. A detailed description criteria used in selection data definition each variables is given. The authors also present analysis conditions database, scalings (power law offset linear) with both dimensional dimensionless variables, predictions expected time
Integrated simulations are performed to establish a physics basis, in conjunction with present tokamak experiments, for the operating modes International Thermonuclear Experimental Reactor (ITER). Simulations of hybrid mode done using both fixed and free-boundary 1.5D transport evolution codes including CRONOS, ONETWO, TSC/TRANSP, TOPICS ASTRA. The is simulated GLF23 CDBM05 energy models. injected powers limited negative ion neutral beam, cyclotron electron heating systems. Several plasma...
A Monte Carlo (MC) impurity code IMPMC has been coupled self-consistently with a divertor SOLDOR/NEUT2D by overcoming the intrinsic problems of MC modelling for transport. is required transport in order to take into account kinetic effect and complex dissociation processes hydrocarbons. The integrated SONIC enables us investigate details including erosion/redeposition on plates further coupling an 3D plasma–surface interaction EDDY. dynamic evolution X-point MARFE observed JT-60U...
The global confinement and the local transport properties of improved core plasmas in JT-60U were studied connection with Er shear formation. In mode internal barriers (ITBs), these are roughly classified into `parabolic type' ITBs `box ITBs. parabolic type ITB has a reduced thermal diffusivity χ region; however, shear, dEr/dr, is not as strong. box very strong at thin layer decreases to level neoclassical there. estimated E × B shearing rate, ωE B, becomes almost same linear growth rate...
With the high-field-side multiple pellet injection into high-triangularity high-βp type I ELMy H-mode discharges, JT-60U has extended density range with a favourable integrated performance. The injected discharge high pedestal pressure compared gas fuelled and temperature does not decrease even at density. At triangularity, βp edge α-parameter increase increasing total βp. Possible linkage among core parameters been proposed based on variety of experiments. Grassy discharges have achieved...
The relationship between particle and heat transport in an internal barrier (ITB) has been systematically investigated reversed shear (RS) high βp mode plasmas of JT-60U. electron effective diffusivity is well correlated with the ion thermal ITB region. ratio flux to flux, calculated on basis linear stability analysis, shows a similar tendency experiment RS plasma strong ITB. However, anomalous smaller than Helium carbon are not accumulated inside even close neoclassical level, but argon...
An integrated SOL/divertor code is being developed by the JAEA (Japan Atomic Energy Agency) for interpretation and prediction studies of behavior plasmas, neutrals, impurities in region. A system consists 2D fluid plasma (SOLDOR), neutral Monte-Carlo (NEUT2D), impurity (IMPMC), particle simulation (PARASOL). The physical processes neutrals are studied using Monte Carlo (MC) to accomplish highly accurate simulations. so-called divertor code, SOLDOR/NEUT2D, has following features: 1) a...
The mitigation of the large pulsed heat loads induced by edge-localized modes (ELMs) on divertor plates is one most important issues for a tokamak fusion reactor. However, ELMs have been completely suppressed in quiescent H-mode (QH-mode) plasmas produced DIII-D (see Burrell K H et al 2002 Plasma Phys. Control. Fusion 44 A253). One key conditions producing QH-mode that direction neutral beam injection (NBI) should be opposite to plasma current (i.e. ctr-NBI), which then leads toroidal...
The slowing-down process of suprathermal alpha particles in a rippled toroidal field is investigated by means an orbit-following Monte-Carlo code. It found that numerical results on the collisionless ripple loss agree fairly well with theoretical predictions. collisional diffusion coefficient for non-ergodic banana derived. ripple-enhanced power during amounts to 10% their total reactor-grade tokamak toroidal-field δ ∼ 1%. fraction particle 1.5 1.8 times as large loss. drift dominates...
The characteristics of the spatial width H-mode pedestal were investigated in hydrogen and deuterium plasmas JT-60U. Both database analysis dedicated experiments on mass scan indicated that depends very weakly plasma particle species or . Identical profiles edge ion temperature Ti obtained with while profile for is not fixed but differs by a factor ∼1.4 (which square root ratio). In addition, an experiment βpol was also performed. Higher had higher value accompanied greater spite almost...
Power exhaust for a 3 GW class fusion reactor with an ITER-sized plasma was investigated by enhancing the radiation loss from seeding impurity. The impurity transport and detachment were simulated under Demo divertor condition using integrated code SONIC, in which Monte-Carlo code, IMPMC, can handle most kinetic effects on ions original formula. simulation results of species low Z (neon) to high (krypton) length exhausted power 500 MW 460 MW, fixed core–edge boundary 7 × 1019 m−3 at first...
The article treats the recent development of quasi-steady ELMy high βp H mode discharges with enhanced confinement and β stability, where long sustainment time, an increase in absolute fusion performance extension discharge regime towards low q95 (∼3) are emphasized. After modification to new W shaped pumped divertor, a heating time (9 s) total energy input 203 MJ became possible without harmful impurity particle recycling. In addition, optimization pressure profile characterized by double...
The dependence of edge stability on plasma shape and local pressure gradients P' in the DIII-D JT-60U tokamaks is studied. stronger shaping allows region discharges with type I (giant) ELMs to have access second for ideal ballooning modes a larger pedestal gradient than ELM discharges. These are near mode first regime limit. results support an based working model as low intermediate toroidal number, n, MHD modes. from analysis indicate that predictions this also consistent observations.
Transient transport experiments are performed in plasmas with and without internal barriers (ITB) on LHD JT-60U. The dependence of χe the electron temperature, Te, temperature gradient, ∇Te, is analysed an empirical non-linear heat model. In ITB, two different types non-linearity observed from cold/heat pulse propagation: depends Te ∇Te JT-60U, while weak LHD. Inside ITB region, there none or both Growth cold driven by negative inside region (LHD) near boundary (JT-60U).