A5013110695- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Physics of Superconductivity and Magnetism
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- Advanced Condensed Matter Physics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Enhanced Oil Recovery Techniques
- Hydraulic Fracturing and Reservoir Analysis
- Theoretical and Computational Physics
- Reservoir Engineering and Simulation Methods
- Magnetic properties of thin films
- Geomagnetism and Paleomagnetism Studies
- Magnetic and transport properties of perovskites and related materials
- Computational Fluid Dynamics and Aerodynamics
- Particle Accelerators and Free-Electron Lasers
- Nuclear Engineering Thermal-Hydraulics
- Gas Dynamics and Kinetic Theory
- Nuclear Materials and Properties
- Quantum chaos and dynamical systems
European Commission
2006-2023
Repsol (Spain)
2004-2007
Directorate-General for Research and Innovation
2006
Ghent University
2003
Joint European Torus
1996-2002
Max Planck Institute for Plasma Physics
1996-2002
Bariloche Atomic Centre
1994-2002
Balseiro Institute
1996-2002
Comisión Nacional de Energía Atómica
1994-2002
Max Planck Computing and Data Facility
2002
The scaling of the energy confinement in H mode plasmas with different hydrogenic isotopes (hydrogen, deuterium, DT and tritium) is investigated JET. For ELM-free modes thermal time τth found to decrease weakly isotope mass (τth ∼M-0.25±0.22), whilst ELMy shows practically no dependence ∼M0.03±0.1). Detailed local transport analysis reveals that edge region increases strongly mass, whereas core decreases (τthcore ∝ M-0.16), approximate agreement theoretical models gyro-Bohm type (τgB ∼M-0.2).
Results are presented from a series of dedicated experiments carried out on JET in tritium, DT, deuterium and hydrogen plasmas to determine the dependence H mode power threshold plasma isotopic mass. The Pthr ∝ Aeff-1 scaling is established over whole range. This result makes it possible for fusion reactor with 50:50 DT mixture access regime about 20% less than that needed DD mixture. first systematic measurements necessary transition type I ELM regime, which occurs after mode, also...
The first measurements of toroidal rotation the bulk plasma during purely ion cyclotron resonance frequency (ICRF) heated H-modes on JET tokamak are reported. Substantial acceleration in direction current occurs at transition into H-mode. In present paper relationship between and improved confinement H-mode is investigated. We conclude that dominant driving mechanism for pressure gradient.
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...
Abstract The recent deuterium–tritium campaign in JET-ILW (DTE2) has provided a unique opportunity to study the isotope dependence of L-H power threshold an ITER-like wall environment (Be and W divertor). Here we present results from dedicated transition experiments at JET-ILW, documenting tritium plasmas, comparing them with matching deuterium hydrogen datasets. From earlier it is known that as plasma isotopic composition changes deuterium, through varying deuterium/hydrogen concentrations,...
Reactor relevant ICRH scenarios have been assessed during DT experiments on the JET tokamak using H mode divertor discharges with ITER-like shapes and safety factors. Deuterium minority heating in tritium plasmas was demonstrated for first time. For 9% deuterium, an power of 6 MW gave 1.66 fusion from reactions between suprathermal deuterons thermal tritons. The Q value steady state discharge reached 0.22 length RF flat-top (2.7 s), corresponding to three plasma energy replacement times....
An overview of JET experimental results in DT plasmas directly relevant to ITER modes operation is presented. Experiments D:T mixtures varying from 100:0 10:90 and those carried out hydrogen show that the H mode threshold power has an approximately inverse isotope mass dependence. Matching some key dimensionless parameters values, similarity experiments with shape safety factor q global energy confinement time practically independent isotopic (~A0.03±0.08), where A atomic hydrogenic species....
We report on transport measurements using the dc flux transformer configuration in clean and twinned single crystals of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$. show that correlated disorder changes not only order solid-liquid phase transition but also nature vortices liquid state. In crystals, melting is shown to take place between a solid vortex lines with no correlation direction magnetic field.
Ion cyclotron resonance heating (ICRH) experiments have been carried out in JET D-T plasmas using scenarios applicable to reactors. Deuterium minority tritium is used for the first time and produces 1.66 MW of fusion power an ICRH 6 MW. The $Q$ value 0.22, which a record steady state discharges. Fundamental $\mathrm{He}{}^{3}$ ICRH, both 50:50 dominated plasmas, generates strong bulk ion temperatures up 13 keV. Second harmonic seen heat mainly electrons as expected conditions. All three...
Third-harmonic ion-cyclotron-resonance heating of ${}^{4}\mathrm{He}$-beam ions has produced for the first time on JET tokamak high-energy populations ${}^{4}\mathrm{He}$ to simulate 3.5 MeV fusion-born alpha (\ensuremath{\alpha}) particles. Acceleration energy range is confirmed by \ensuremath{\gamma}-ray emission from nuclear reaction ${}^{9}\mathrm{Be}(\ensuremath{\alpha},n\ensuremath{\gamma}){}^{12}\mathrm{C}$ and excitation Alfv\'en eigenmodes. Concomitant electron sawtooth...
We report on a strongly pinned entangled vortex liquid above the critical point (CP) of first-order melting transition in untwinned ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ single crystals. Above CP, $\mathbf{c}$ axis dissipation is finite where in-plane undetectable, implying large pinning presence cutting and recombination. demonstrate that behavior CP governed by pointlike disorder. The same reproduced twinned samples with proton-induced defects.
Results of experiments investigating the performance JET Mark IIA divertor are reported and compared with its I predecessor. The principal effect reducing width (increasing closure) was to increase pumping for both deuterium impurities while upstream neutral pressure. Neither orientation target relative plasma nor had a major influence on core in ELMy H modes. Changing triangularity thus edge magnetic shear modifies ELM frequency mode plasmas, thereby changing peak power loading. integrated...
Transport measurements using the dc flux transformer configuration together with $c$-axis resistance data in clean and twinned $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ single crystals show that vortices are localized by twin-boundary potential. The results support existence of a divergent tilt modulus [D. R. Nelson V. M. Vinokur, Phys. Rev. B 48, 13 060 (1993)] liquid freezes into Bose glass.
Plasmas heated by ICRF only in the JET tokamak show distinct structures toroidal rotation profile, with regions where dω/dr>0 when minority cyclotron resonance layer is far off-axis. The dominantly co-current a clear off-axis maximum. There slight difference between high-field side (HFS) or low-field position of this layer: maximum profile modestly higher for HFS position. This contrast to predictions theories that rely mainly on effects arising from ICRF-driven fast ions account...
We report on combined transport and magnetic decoration studies of pinned moving vortex structures in the low-field (100 Oe) regime. Thermal current annealing processes show that equilibrium state array has fewer topological defects than observed when structure first starts to become unpinned, more at high velocities. This is agreement with recent experiments theoretical results. \textcopyright{} 1996 The American Physical Society.
ELMy H-modes in helium-4 plasmas provide valuable information on H-mode physics as well a possible early low activation operational phase for next-step tokamaks, such ITER. With this mind, series of experiments were performed JET with pure NBI auxiliary heating (up to 12 MW). A set produced, both the Type I ELM regime and second regime, which showed characteristics similar deuterium III but reverse frequency dependence power. Sawteeth also observed, had behaviour those seen deuterium....
Recent progress towards obtaining high density and confinement in JET as required for the ITER reference scenario at Q = 10 is summarized. Plasmas with simultaneous H98(y,2) 1 densities up to n/nGW~1 are now routinely obtained. This has been possible (i) by using plasmas (δ~0.5) medium (δ~0.3-0.4) triangularity sufficient heating power maintain Type I ELMs, (ii) impurity seeded low (δ⩽0.2) triangularity, (iii) an optimized pellet injection sequence, maintaining energy raising density, (iv)...
ELMy H-mode experiments at JET in 2000/mid-2002 have focused on discharges with normalized parameters for plasma density, energy confinement and beta similar to those of the ITER QDT = 10 reference regime (n/nGW ∼ 0.85, H98(y,2) 1, βN 1.8). plasmas been realized reaching or even exceeding steady-state conditions (up 5 s 12 τE) a reproducible way only limited by duration additional heating phase. These results obtained (a) highly triangular plasmas, increasing average triangularity δ towards...
Ion cyclotron resonance frequencies (ICRF) mode conversion has been developed for localized on-axis and off-axis bulk electron heating on the JET tokamak. The fast magnetosonic waves launched from low-field side ICRF antennas are mode-converted to short-wavelength high-field of 3He ion layer in D 4He plasmas subsequently damped electrons. resulting power deposition, measured using modulation, is narrow with a typical full-width at half-maximum ≈30 cm (i.e. about 30% minor radius) total...
1 H-mode access studies under conditions of very low plasma density provide valuable information on the physics edge transport barrier formation and are an important part operational scenario development for next step fusion device, ITER. JET operation with a electron density, , MkII gas box septum divertor was found to have significant effect power threshold L–H transition, Pth. A sharp 'turning point' below which Pth increases decreasing is Ip/Bt values 2.5 MA/2.7 T, MA/2.6 MA/2.4 T 2.2 T....
A number of experiments with heating DT plasmas using ICRF waves have been carried out at JET. The results these analysed by comparing experimentally measured quantities the numerical simulations. In particular, four scenarios examined: (a) minority (∼5-20%) deuterons fundamental ion cyclotron frequency, ω = ωcD; (b) second harmonic tritium, 2ωcT; (c) 3He a few per cent 3He; (d) deuterium, 2ωcD. An important aim analysis was to assess whether present understanding physics is adequate for...
Experiments on the JET tokamak show that wave-induced pinch in presence of toroidally asymmetric waves can provide a tool for controlling profile ion-cyclotron-resonant $^{\mathrm{3}}\mathrm{H}\mathrm{e}$ ions. Direct evidence has been obtained from measured $\ensuremath{\gamma}$-ray emission profiles. Concurrent differences excitation Alfv\'en eigenmodes (AEs), sawtooth stabilization, electron temperatures, and fast-ion stored energies are observed. The location AEs profiles consistent with...
Helium 3 minority fuel ions have been observed to be accelerated megaelectron-volt (MeV) energies by ion cyclotron radiofrequency (ICRF) heating. These energetic undergo nuclear reactions with impurity 9Be and 12C in the plasma, characteristic gamma radiation is emitted. For special circumstances, this ray emission has detected a 19 channel profile monitor constructed primarily for neutron measurements. Two-dimensional (2-D) profiles of derived tomographic reconstruction; these correspond...
Abstract An experimental study of immiscible WAG (water-alternating gas) injection is presented. The target reservoir the waterflooded Troncoso sandstone in Chihuido de la Sierra Negra Field Argentina. original fluid was an undersaturated light oil with a viscosity about 1 cp and 13 to 20 mole percent carbon dioxide. Phase behavior tests were conducted using live synthetic candidate gases. They aimed at assessing extent which compositional effects could affect recovery current pressure....