A5025736130- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- Superconducting Materials and Applications
- Theoretical and Computational Physics
- Complex Systems and Time Series Analysis
- Advanced Chemical Physics Studies
- Nuclear Materials and Properties
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Fluid Dynamics and Turbulent Flows
- Nuclear Physics and Applications
- Spectroscopy and Laser Applications
- earthquake and tectonic studies
- Combustion and flame dynamics
- Laser-induced spectroscopy and plasma
- Physics of Superconductivity and Magnetism
- Advanced Combustion Engine Technologies
- Meteorological Phenomena and Simulations
- Spectroscopy and Quantum Chemical Studies
CEA Cadarache
2013-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2002-2023
Royal Military Academy
2020
Culham Science Centre
2014
Centre National de la Recherche Scientifique
1992-2009
Aix-Marseille Université
2009
École Polytechnique
1987-2002
University of California, San Diego
2002
École Normale Supérieure - PSL
2002
Probe measurements in the PISCES linear device indicate presence of plasma radially far from where it is produced. We show that this mainly caused by large-scale structures with high radial velocity. Data Tore Supra tokamak striking similarities shape these intermittent events as well fluctuation density probability distribution and frequency spectrum. The fact intermittent, are so similar devices tokamaks indicates universality convective transport magnetically confined plasmas.
The nature of intermittency, long observed in magnetic fusion devices, was revisited lately [G. Antar et al., Phys. Rev. Lett. 87, 065001 (2001)]. It shown that intermittency is caused by large-scale events with high radial velocity reaching about 1/10th the sound speed. These type structures were named “avaloids.” In present article, universality convective turbulence magnetically confined plasmas investigated. Turbulence properties scrape-off layer four different devices are compared....
With WEST (Tungsten Environment in Steady State Tokamak) (Bucalossi et al 2014 Fusion Eng. Des. 89 907–12), the Tore Supra facility and team expertise (Dumont Plasma Phys. Control. 56 075020) is used to pave way towards ITER divertor procurement operation. It consists implementing a configuration installing ITER-like actively cooled tungsten monoblocks tokamak, taking full benefit of its unique long-pulse capability. user platform, open all partners. This paper describes physics basis WEST:...
Abstract WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up 1000 s. In support of ITER operation and DEMO conceptual activities, key missions are: (i) qualification high heat flux plasma-facing components integrating both technological physics aspects relevant particle exhaust conditions, particularly for the monoblocks foreseen divertor; (ii) integrated steady-state at confinement, with a focus on power issues. During phase...
Experiments in the tokamaks TEXTOR, CASTOR, T-10 and ISTTOK, as well reversed field pinch RFX have provided new complementary evidence on physics of universal mechanism E×B velocity shear stabilization turbulence, concomitant transport barrier formation radial conductivity by using various edge biasing techniques.
Density fluctuation measured by a reciprocating Langmuir probe on the Tore Supra tokamak [Garbet et al., Nucl. Fusion 32, 2147 (1992)] is investigated. The purpose of this article to give rather comprehensive analysis intermittency using several data analyses compare bursts properties that coherent structures and avalanches. probability distribution density fluctuations found positively skewed, while Gaussian shape for negative values recorded. It shown spectra possess one scaling region...
Abstract The choice of first wall material is paramount importance for the plasma start-up conditions in ITER and future fusion power plants. In this context, present work focuses on correlations between impurity sources total radiated during tungsten (W) Environment Steady-state Tokamak (WEST). objective to highlight experimental indications a preferable combination scenario materials. Until 2019, WEST featured full high Z with all limiters exposing only W surfaces plasma. To study impact...
A collective infra-red laser scattering diagnostic has been installed on the TORE SUPRA tokamak for measurement of plasma density fluctuations. For range wavenumbers explored (3-15 cm-1), angles are very weak ( approximately 1 mrad). Consequently, signals averaged along whole observation chord, resulting in poor longitudinal spatial localization. By virtue pitch angle variation magnetic field lines tokamak, and perpendicularity turbulence wavevector to these lines, it possible obtain partial...
Upgrade of the Tore Supra ergodic divertor (ED) has led to significant progress in ED physics. Pulse durations 30?s with LHCD have been achieved demonstrating heat exhaust capability both actively cooled technology at hand and this specific concept. The disruptive limit governed by stochastization outer magnetic surfaces is found occur for a value Chirikov parameter reaching two on surface q = 2+(3/12). This experimentally observed robustness allows one operate very low safety factor...
The extraction of H− ions from a volume source is greatly improved by the presence weak magnetic field parallel to plasma electrode that magnetically insulates this bulk plasma. When biased positive, depletes electron population in neighboring region. To maintain neutrality, negative main replace electrons Thus high fraction builds up front electrode. implications these phenomena for ion beam formation are discussed.
This article reports work in progress on laser diagnostics of negative-ion transport velocity H−-ion volume sources. The plasma dynamics after the shot is discussed detail, and effect potential perturbation H− velocities evaluated. A method evaluation from single-laser-beam photodetachment experiments proposed. To substantiate this method, two-laser-beam have been effected. thus determined are pressure dependent; they correspond to energies range 0.23–0.08 eV.
A collective laser light scattering diagnostic ALTAIR (a french acronym for local analysis of anomalous transport using infrared light), a CO2 beam (λ=10.6 μm) has been realized to measure plasma density fluctuations in the TORE SUPRA tokamak. This article describes detail optical setup, signal processing, acquisition, and control systems required this experiment. As propagating tokamaks have small wave numbers require angles, such experiments are considered as having no resolution along...
For the first time, internal magnetic turbulence is measured by a new cross polarization scattering diagnostic in Tore Supra tokamak. The principle of this experiment presented. It based on change or mode conversion electromagnetic wave scattered fluctuations. A strong correlation between fluctuation and additional heating observed, contrary to edge observed fluctuations increase linearly with poloidal beta number ${\ensuremath{\beta}}_{p}$ L-mode confinement regime.
The ion current collected by a probe in magnetized plasma is sensitive to the angle between its surface and flow streamlines. This intuitive concept basis of Gundestrup probe, polar array planar collectors mounted around an insulating housing. Probe theory for measuring flows has been developed on two fronts: Recent kinetic fluid models, reviewed here, give similar predictions within range applicability model assumptions. A comparison with measurements rotating Mach CASTOR tokamak (Czech...
The former all-carbon wall on JET has been replaced with beryllium in the main torus and tungsten divertor to mimic surface materials envisaged for ITER. Comparisons are presented between type I H-mode characteristics each design by examining respective scans over deuterium fuelling impurity seeding, required ameliorate exhaust loads both at full capability Attention is focused upon a common high-triangularity, single-null configuration 2.5 MA, q95 ≈ 3.5 yielding most robust all-C...
Abstract Achieving a successful plasma current ramp-up in full tungsten tokamak can be challenging due to the large core radiation (and resulting low temperature) that faced with this heavy metallic impurity if its relative concentration is too high. Nitrogen injection during of WEST discharges greatly improves temperature and magnetohydrodynamic (MHD) stability. Experimental measurements integrated simulations RAPTOR code, complemented QuaLiKiz neural network for computing turbulent...
The parallel Kelvin–Helmholtz instability is investigated as a possible explanation for poloidal asymmetries of density fluctuations which reverse with the plasma current direction. It shown that these modes are localized around position where radial gradient velocity maximum. Two mechanisms lead to unstable modes; acceleration ions in presheath and anomalous Stringer spin-up due particle flux. Up–down explained by combining two effects. Depending on limiter configuration, effect amplifies...
Photodetachment cross sections for WO−3 have been measured near the detachment threshold (3.0–3.7 eV). A fast beam of is merged with a coaxial cw laser and photodetached electrons are detected magnetic confinement slow electron collector. The photodetachment spectrum yields an affinity WO3 3.33+0.08−0.15 eV, somewhat lower than values obtained in thermodynamic equilibrium measurements. In addition, limit 3.7 eV HWO4.
Results on confinement and turbulence from a set of Ohmic discharges in TORE SUPRA are discussed. Attention is focused the saturation energy time it emphasized that this can be explained by electron heat diffusivity. The ion behaviour indeed governed dilution equipartition effects. Although transport never neoclassical, there no enhanced degradation at saturation. This confirmed measurements using CO2 laser coherent scattering. level density fluctuations follows diffusivity variations with...
A diagnostic method has been devised and used to measure local transport velocities of negative hydrogen ions (${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$) within a gas-discharge source chamber. The is based on laser-pulse photodetachment ions, inducing changes in the electron ion densities, whose space time evolution are traced detail by means laser pulses probes. technique, which general applicability, can be plasmas where conventional probe or spectroscopic methods not practicable. new...
Ripple-induced thermal loss effect on plasma rotation is investigated in a set of Ohmic L-mode plasmas performed Tore Supra, and comparisons with neoclassical predictions including ripple are performed. Adjusting the size plasma, amplitude has been varied from 0.5% to 5.5% at boundary, keeping edge safety factor constant. The toroidal flow dynamics understood as being likely dominated by turbulence transport driven processes low amplitude, while ripple-induced friction becomes dominant high...