A5030815910- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Nuclear Materials and Properties
- Ionosphere and magnetosphere dynamics
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- Dust and Plasma Wave Phenomena
- Numerical methods in inverse problems
- Electrohydrodynamics and Fluid Dynamics
- Metallurgical Processes and Thermodynamics
- Atomic and Molecular Physics
- Historical and Literary Analyses
- Antenna Design and Optimization
- Historical and Literary Studies
- Computational Fluid Dynamics and Aerodynamics
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Geophysical Methods and Applications
- Antenna Design and Analysis
Royal Military Academy
2020
Centre National de la Recherche Scientifique
2006-2019
Institut Jean Lamour
2015-2019
Université de Lorraine
2006-2019
Max Planck Institute for Plasma Physics
2009-2017
Max Planck Institute for Plasma Physics - Greifswald
2011-2016
Culham Science Centre
2010-2016
Max Planck Society
2009-2015
Culham Centre for Fusion Energy
2012-2015
Ghent University
2015
JET underwent a transformation from full carbon-dominated tokamak to fully metallic device with beryllium in the main chamber and tungsten divertor. This material combination is foreseen for activated phase of ITER. The ITER-Like Wall (ILW) experiment at shall demonstrate plasma compatibility walls reduction fuel retention. We report on set experiments (Ip = 2.0 MA, Bt 2.0–2.4 T, δ 0.2–0.4) different confinement conditions global gas balance analysis demonstrating strong long-term retention...
This paper reports the impact on confinement and power load of high-shape 2.5 MA ELMy H-mode scenario at JET a change from all carbon plasma-facing components to an metal wall. In preparation this change, systematic studies reduction as result fuelling in combination with nitrogen seeding were carried out JET-C are compared their counterpart metallic An unexpected significant is reported decrease pedestal but partially recovered injection nitrogen.
The original goals of the JET ITER-like wall included study impact an all W divertor on plasma operation (Coenen et al 2013 Nucl. Fusion 53 073043) and fuel retention (Brezinsek 083023). ITER has recently decided to install a full-tungsten (W) from start operations. One key inputs required in support this decision was possibility melting melt splashing during transients. Damage type can lead modifications surface topology which could higher disruption frequency or compromise subsequent...
Disruptions are a major operational concern for next generation tokamaks, including ITER.They may generate excessive heat loads on plasma facing components, large electromagnetic forces in the machine structures and several MA of multi-MeV runaway electrons.A more complete understanding processes methods to suppress them is necessary ensure safe reliable operation future tokamaks.Runaway electrons were studied at JET-ILW showing that their dependencies (accelerating electric field, avalanche...
This paper reports the progress made at JET-ILW on integrating requirements of reference ITER baseline scenario with normalized confinement factor 1, a pressure 1.8 together partially detached divertor whilst maintaining these conditions over many energy times. The 2.5 MA high triangularity ELMy H-modes are studied two different configurations D-gas injection and nitrogen seeding. power load reduction N seeding is reported. relationship between an increase in pedestal investigated....
The effective sputtering yield of Be (Y tot ) was determined in-situ by emission spectroscopy low ionising as function the deuteron impact energy (E in = 25 -175eV and surface temperature (T surf 200 • C -520 C) limiter discharges carried out JET tokamak.Be self dominates erosion at high energies > 150eV causes Y far beyond 1.The drops to values, below 4.5%, accessible lowest ≃ 25eV achievable configuration.At medium energies, E 75eV , two contributors measured 9% were identified: third...
Experiments on JET with a carbon-fibre composite wall have explored the reduction of steady-state power load in an ELMy H-mode scenario at high Greenwald fraction ∼0.8, constant and close to L H transition. This paper reports systematic study due effect fuelling combination seeding over wide range pedestal density ((4–8) × 1019 m−3) detailed documentation divertor, main plasma conditions, as well comparative two extrinsic impurity nitrogen neon. It also impact overall behaviour, possible...
Recent experiments at JET combining reciprocating probe measurements upstream and infrared thermography the plasma-facing components (PFC) on plasmas in limiter configurations show that common approach to predicting power load underestimates heat flux contact point by a factor 1.5–3. The current model scaling laws used for onto first wall during ramp-up/down ITER are uncertain better understanding of transport PFCs is required. loads usually predicted projecting parallel associated with...
For the new ITER-like wall at JET, two infrared diagnostics (KL9B, KL3B) have been installed. These can operate between 3.5 and 5 μm up to sampling frequencies of ∼20 kHz. KL9B KL3B image horizontal vertical tiles divertor. The divertor are tungsten coated carbon fiber composite except central tile which is bulk consists lamella segments. thermal emission lamellae affects surface temperature measurement therefore KL9A has upgraded achieve a higher spatial resolution (by factor 2). A...
For the design and operation of large fusion devices a detailed understanding power exhaust processes is necessary.This paper will give an overview current research on divertor load mechanisms.The results shown are obtained in JET with ITER like wall ASDEX Upgrade tungsten coated plasma facing components.The challenges infrared thermography bulk presented.For steady state heat load, fall-off length λ q JET-ILW compared to empirical scaling found carbon components.A first attempt scale...
The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite requires active protection to prevent excessive heat loads on plasma facing components (PFC). Analog CCD cameras operating in near infrared wavelength are used measure surface temperature PFCs. Region interest (ROI) analysis performed real time maximum measured each ROI sent vessel thermal map. system started October 2011 has already successfully led a safe landing when hot...
The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode, ΔW 0.7 MJ mitigated edge localized modes (ELMs). Tungsten (W) is the material now decided for divertor plasma-facing components from start plasma operations. W atoms sputtered targets during ELMs are expected to be dominant source under partially detached conditions required safe operation. impurity concentration in core can dramatically degrade its performance lead potentially damaging...
A new pellet injection system was installed at JET designed for both fuelling and ELM pacing. The purpose of the pacing section to validate as a suitable tool mitigation in ITER. Pellet confirmed large size scale JET. dynamics triggered ELMs investigated with respect their spontaneous counterparts. Triggered show features also typical several operational regimes. Since none these regimes unsettled by pellets this is strong hint compatibility other plasma control tools. Observations modelling...
The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode be achieved tungsten (W) divertor. W atoms sputtered from divertor targets during mitigated ELMs are expected to the dominant source in ITER. impurity concentration plasma core can dramatically degrade its performance lead potentially damaging disruptions. Understanding physics target due sputtering inter-ELMs is important helped by experimental measurements improved precision. It has...
At JET the error field correction coils can be used to generate an n = 1 or 2 magnetic perturbation (Liang et al 2007 Plasma Phys. Control. Fusion 49 B581). Various experiments at have already been carried out investigate mitigation of ELMs by resonant perturbations (RMPs) 2010 Nucl. 50 025013, Liang 2011 51 073001). However, typical formation a secondary strike point (strike splitting) RMPs observed in other machines (Jakubowski Contrib. 701–7, Jakubowski 2004 44 S1–11, Nardon J. Mater. 415...
Nonlinear magneto-hydrodynamic (MHD) simulations with the JOREK code may be used to improve our understanding of edge-localized-modes (ELMs) (Huysmans and Czarny 2007 Nucl. Fusion 47 659–66, Huysmans et al 2009 Plasma Phys. Control. 51 124012, Pamela 2010 52 075006). These H-mode related instabilities cause some damage tungsten divertor ITER (Bazylev Scr. T128 229–33), it was demonstrated experimentally that ELM energy losses increase both machine size decreasing collisionality (ITER Physics...
The EDGE2D-EIRENE code is applied for simulation of divertor detachment during matched density ramp experiments in high triangularity, L-mode plasmas both JET-Carbon (JET-C) and JET-ITER-Like Wall (JET-ILW). runs without drifts includes either C or Be as impurity, but not W, assuming that the W targets have been coated with via main chamber migration. simulations reproduce reasonably well observed particle flux raised JET-C JET-ILW can better match experimental in-out target power asymmetry...
Abstract L to H transition studies at JET have revealed an n = 0, m 1 magnetic oscillation starting immediately the (called M-mode for brevity). While is present a weak ELM-less H-mode regime obtained, with clear increase of density and electron temperature pedestal. It intermediate state between H-mode. In ICRH heated plasmas or low NBI mode pedestal can remain steady (with small oscillations) duration heating phase, order 10 s more. The axisymmetric has period ~0.5–2 ms, poloidal number 1:...
Abstract In high confinement mode, highly shaped plasmas with edge localized modes in JET, and for heating power of 15–17 MW, the fluid code EDGE2D-EIRENE predicts transition to detachment assisted by nitrogen at low field side (LFS) target when more than 50% crossing separatrix between ELMs is radiated divertor chamber, i.e. ~4 MW. This observed both ITER-like wall (JET-ILW) carbon (JET-C) configurations consistent experimental observations within their uncertainty. these conditions, peak...
We report the identification of a localized current structure inside JET plasma. It is field-aligned closed helical ribbon, carrying in same direction as background profile (cocurrent), rotating toroidally with ion velocity (corotating). appears to be located at flat spot plasma pressure profile, top pedestal. The spontaneously low density, high rotation plasmas, and can last up 1.4 s, time comparable local resistive time. considerably delays appearance first edge mode.Received 23 November...
One of the most severe problems for fusion reactors is power load on plasma facing components. The challenge to develop operation scenarios, which combine sufficient energy confinement with benign heat loads radiative type-III ELMy H-mode seems a possible solution such an integrated ITER scenario. Nitrogen seeded H-modes standard inductive scenario and high beta stationary hybrid are investigated respect their transient steady-state fluxes divertor, properties, edge operational space, core...
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...
A Vlasov code is used to model the transition region between an equilibrium plasma and absorbing wall in presence of a tilted magnetic field, for case weakly collisional (λmfp≫ρi, where λmfp ion-neutral mean-free path ρi ion Larmor radius). The phase space structure plasma-wall analyzed detail theoretical estimates presheath width are tested numerically. It shown that distribution near far from Maxwellian, so temperature measurements should be interpreted with care. Particular attention...