A5029131247- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Nuclear Materials and Properties
- Nuclear and radioactivity studies
- Model Reduction and Neural Networks
- Software Engineering Research
- Textile materials and evaluations
- Vibration and Dynamic Analysis
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- IoT Networks and Protocols
- Sugarcane Cultivation and Processing
- Electrostatic Discharge in Electronics
- Atomic and Subatomic Physics Research
- Solar and Space Plasma Dynamics
- Nuclear physics research studies
- Open Source Software Innovations
- Building Energy and Comfort Optimization
Culham Centre for Fusion Energy
2014-2020
Culham Science Centre
2010-2020
Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento
2006-2017
Instituto Superior de Tecnologias Avançadas
2009-2014
Instituto Superior Técnico
1996-2014
Max Planck Society
2014
University of Lisbon
2004-2014
Aalto University
2013
Instituto Politécnico de Lisboa
2005-2013
ITER
2013
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...
The onset of a neoclassical tearing mode (NTM) depends on the existence large enough seed island. It is shown in Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, alpha particles strongly stabilize sawteeth. also that, adding and drive just outside inversion radius, sawteeth are destabilized, resulting shorter...
The behaviour of tungsten in the core hybrid scenario plasmas JET with ITER-like wall is analysed and modelled a combination neoclassical gyrokinetic codes. In these discharges, good confinement conditions can be maintained only for first 2?3?s high power phase. Later W accumulation regularly observed, often accompanied by onset magneto-hydrodynamical activity, particular tearing modes (NTMs), both which have detrimental effects on global energy confinement. dynamics process examined, taking...
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 impact of carbon and beryllium/tungsten as plasma-facing components on plasma radiation, divertor power particle fluxes, neutral conditions in the divertors has been assessed JET both experimentally by edge fluid code simulations for plasmas low-confinement mode. In high-recycling studies show a 30% reduction total radiation scrape-off (SOL) layer when replacing (JET-C) with beryllium main chamber tungsten (JET-ILW). Correspondingly, at low-field side (LFS) plate two-fold increase...
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....
In 2003, the performance of 'hybrid' regime was successfully validated in JET experiments up to βN = 2.8 at low toroidal field (1.7 T), with plasma triangularity and normalized Larmor radius (ρ*) corresponding identical ASDEX Upgrade discharges. Stationary conditions have been achieved fusion figure merit ( ) reaching 0.42 q95 3.9. The discharges show similar MHD, edge current profile behaviour, when compared Upgrade. addition, extended hybrid scenario operation higher 2.4 T lower ρ* towards...
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...
An overview is given of the experimental method, analysis technique and results for trace tritium experiments conducted on JET tokamak in 2003. Observations associated with events such as sawtooth collapses, neo-classical tearing modes edge localized are described. Tritium transport seen to approach levels plasma core at high density low q(95), barrier region internal (ITB) discharges. remains well above all other cases. The correlation measured diffusion coefficient convection velocity...
The ITER Scenario Modelling Working Group (ISM WG) is organized within the European Task Force on Integrated Tokamak (ITM-TF). main responsibility of WG to advance a pan-European approach integrated predictive modelling plasmas with emphasis urgent issues, identified during Design Review. Three major topics are discussed, which considered as and where has best possible expertize. These current profile control, density control impurity in (the last two involve both core SOL plasma). Different...
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 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...
The paper presents the results of 1.5-dimensional simulations density profiles and pellet fuelling for ITER baseline scenario performed with ASTRA JETTO transport codes by Scenario Modelling working group within European Task Force on Integrated Tokamak Modelling. first part describes physics problem how it is implemented in different available to group. second simulations. Results obtained GLF23 based model a simplified description particle source are described alongside simpler...
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...
Radiative divertor operation in JET high confinement mode plasmas with the ITER-like wall has been experimentally investigated and simulated EDGE2D-EIRENE horizontal vertical low field side (LFS) configurations. The simulations show that LFS heat fluxes are reduced N2-injection similar fashion both configurations, qualitatively consistent experimental observations. no substantial difference between two configurations reduction of peak flux as a function radiation, nitrogen concentration, or...
Since it is uncertain if ITER operation compatible with type-I edge localized modes (ELMs), the study of alternative ELM regimes an urgent issue.This paper reports on experiments JET aiming to find scenarios small ELMs and good confinement, such as type-II in ASDEX Upgrade, enhanced D-alpha H-mode Alcator C-mod or grassy JT-60U.The includes shape variations, especially closeness a double-null configuration, variations q 95 , density beta poloidal.H-mode pedestals without have been observed...
The formation of magnetic islands with mode numbers (m>1,n⩾1) apparently triggered by sawtooth crashes has for a long time been concern in JET discharges auxiliary heating as it affects the peak performance, terms stored energy or neutron yield (in DT experiments). phenomenological association crash onset resistive modes is particularly relevant context neo-classical tearing (NTM) theory that requires `seed' island above critical value. Relying on observations and an understanding role...
A new scenario to delay or prevent neoclassical tearing mode (NTM) onset is presented. By active sawtooth destabilization, short period and low amplitude sawteeth are generated, such that the produced NTM seed island reduced threshold normalized plasma pressure for triggering of NTMs, βNonset, increased. The has been explored experimentally in Joint European Torus (JET). Ion cyclotron resonance frequency (ICRF) waves tuned 2nd harmonic H-minority have used control. Whereas ICRF generally...
Experiments performed at JET during the past two years show that, in high triangularity H-mode plasmas with Ip = 2.5 MA, ne/nGr ≈ 1.0, it is possible to radiate separately up ≈40% of total injected power on closed flux surfaces pedestal region (argon seeding) and ≈50% divertor (nitrogen seeding), while maintaining confinement improvement factor value required for ITER, H98(y, 2) 1.0. The radiated fraction achieved both cases (65–70%) close that ITER. However, Type I ELMs observed impurity...
Results are presented from the JET Trace Tritium Experimental (TTE) campaign using minority tritium (T) plasmas (n(T)/n(D) 2 MA) and monotonic q-profiles. In CH discharges gamma-ray emission decay times much lower than classical (tau(Ts) + tau(alpha s)), indicating alpha confinement degradation, due to orbit losses particle drift predicted by a 3-D Fokker-Planck numerical code modelled TRANSP.
In anticipation of revised operational limits accompanying upgrade the JET tokamak to an all-metal, ITER-like wall, systematic studies have been conducted moderating divertor heat load in type I ELMy H-mode by enhanced deuterium fuelling and seeding with extrinsic impurities neon or nitrogen. These were found differ mainly roughly ten times higher level nitrogen than presently required approach outboard detachment, their effects upon ELMs. With either species up input power ?17?MW, strongly...
The dynamics for the transition from L-mode to a stationary high Q DT H-mode regime in ITER is expected be qualitatively different present experiment due low fuelling efficiency of recycling neutrals, that influence post plasma density evolution, and effect evolution itself both on alpha heating power edge flow required sustain confinement itself.This paper presents results modelling studies with JINTRAC suite codes, which include optimisation ensure robust achievement regimes one hand...