A5079715510- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Advanced Data Storage Technologies
- Plasma Diagnostics and Applications
- Network Security and Intrusion Detection
- Nuclear Materials and Properties
- Anomaly Detection Techniques and Applications
- Fault Detection and Control Systems
- Atomic and Subatomic Physics Research
- Physics of Superconductivity and Magnetism
- Nuclear Physics and Applications
- Electromagnetic Launch and Propulsion Technology
- Distributed and Parallel Computing Systems
- Advanced Chemical Physics Studies
- High-Energy Particle Collisions Research
- Sensor Technology and Measurement Systems
- Parallel Computing and Optimization Techniques
- Real-time simulation and control systems
- Spectroscopy and Laser Applications
- Quantum, superfluid, helium dynamics
Culham Centre for Fusion Energy
2009-2024
Culham Science Centre
2015-2024
United Kingdom Atomic Energy Authority
2004-2024
Royal Military Academy
2020
Forschungszentrum Jülich
2002-2009
Queen's University Belfast
2009
Universidad Politécnica de Madrid
2009
Joint European Torus
2000-2003
CEA Cadarache
2002
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2002
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 JET exploitation plan foresees D–T operations in 2020 (DTE2). With respect to the first campaign 1997 (DTE1), when was equipped with a carbon wall, experiments will be conducted presence of beryllium–tungsten ITER-like wall and benefit from an extended improved set diagnostics higher additional heating power (32 MW neutral beam injection + 8 ion cyclotron resonance heating). There are several challenges presented by new wall: general deterioration pedestal confinement; risk heavy...
Abstract After the second Deuterium–Tritium Campaign (DTE2) in JET tokamak with ITER-Like Wall (ILW) and full tritium campaigns that preceded followed after DTE2, a sequence of fuel recovery methods was applied to promote removal from wall components. The started several days baking main chamber walls at 240 °C 320 °C. Subsequently, superimposed Ion-Cyclotron Conditioning (ICWC) Glow Discharge (GDC) cleaning cycles deuterium. Diverted plasma operation deuterium different strike point...
Real-time simultaneous control of several radially distributed magnetic and kinetic plasma parameters is being investigated on JET, in view developing integrated advanced tokamak scenarios. This paper describes the new model-based profile controller which has been implemented during 2006–2007 experimental campaigns. The aims to use combination heating current drive (H&CD) systems—and optionally poloidal field (PF) system—in an optimal way regulate evolution parameter profiles such as...
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...
Abstract The present paper is devoted to a first assessment of the DEMO diagnostics systems and controls in context pulsed steady state reactor design under study Europe. In particular, main arguments treated are: (i) quantities be measured requirements for measurements; (ii) capability diagnostic control technology, determining most urgent gaps, (iii) program strategy research development (R&D) needed fill gaps. Burn control, magnetohydrodynamic stability, basic machine protection...
Burning plasmas with 500 MW of fusion power on ITER will rely partially detached divertor operation to keep target heat loads at manageable levels. Such regimes be maintained by a real-time control system using the seeding radiative impurities like nitrogen (N), neon or argon as actuator and one more diagnostic signals sensors. Recently, detachment has been successfully achieved in Type I ELMy H-mode JET-ITER-like wall discharges saturation current (Isat) measurements from Langmuir probes...
A neoclassical tearing mode (NTM) requires a finite size seed island to become unstable. Usually the local pressure gradient is relatively large at β-values needed for these islands destabilize NTMs. Therefore, has growth rate onset and grows rapidly its saturated width. This width proportional β as long it well above marginal β-limit below which stable. The independent of trigger mechanism provides detailed information on stabilizing terms in modified Rutherford equation, are not...
In order to simultaneously control the current and pressure profiles in high performance tokamak plasmas with internal transport barriers (ITB), a multi-variable model-based technique has been proposed. New algorithms using truncated singular value decomposition (TSVD) of linearized model operator retaining distributed nature system have implemented JET system. Their simplest versions applied density profile reversed shear three heating drive actuators (neutral beam injection, ion cyclotron...
This paper describes a new technique which has been implemented on the JET tokamak to investigate integrated real-time control of several plasma profiles simultaneously (such as current, temperature and pressure) reports results first experimental tests. The are handled through their projection suitable basis functions according Galerkin scheme. Their response three actuators (heating current drive powers injected in plasma) is linearized an experimentally deduced multi-input multi-output...
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...
In JET, advanced tokamak research mainly focuses on plasmas with internal transport barriers (ITBs) that are strongly influenced by the current density profile. A previously developed optimized shear regime low magnetic in plasma centre has been extended to deeply negative configurations. High fusion performance wide ITBs obtained transiently central configuration: HIPB98(y,2) ∼ 1.9, βN = 2.4 at Ip 2.5 MA. At somewhat reduced performance, electron and ion have sustained full drive operation...
Recent JET experiments have been devoted to the study of (3He)–D plasmas involving radio frequency (RF) heating. This paper starts by discussing RF heating efficiency theoretically expected in such plasmas, covering both relevant aspects wave and particle dynamics. Then it gives a concise summary main conclusions drawn from recent that were either focusing on studying physics or adopting as tool plasma behavior. Depending minority concentration chosen, different physical phenomena are...
The recent development of real-time measurements and control tools in JET has enhanced the reliability reproducibility relevant ITER scenarios. Diagnostics such as charge exchange, interfero-polarimetry, electron cyclotron emission have been upgraded for measurements. In addition, processes like magnetic equilibrium q profile reconstruction developed applied successfully experiments using model based techniques. Plasma operation against magnetohydrodynamic instabilities are also benefiting...
We present the results of recent experiments related to real-time control internal transport barriers (ITBs) in JET. Using a simple criterion characterize ITB existence, location and strength, we have successfully controlled for first time radial electron temperature profile within ITB. The dimensionless variable used algorithm - ratio ion gyro-radius local gradient scale length is measure normalized characterizes satisfactorily main features with relatively low computational cost. show...
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...
Experimental evidence from the JET tokamak is presented supporting predictions of a recent theory (Graves et al 2009 Phys.Rev. Lett.102 065005) on sawtooth instability control by toroidally propagating ion cyclotron resonance waves.Novel experimental conditions minimized possible alternate effect magnetic shear modification current drive, and enabled dependence new energetic mechanism to be tested over key variables.The results have favourable implications waves in fusion reactor.
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...
In this paper, we present the work in implementation of a new calibration for JET real-time polarimeter based on complex amplitude ratio technique and self-validation mechanism data. This allowed easy integration polarimetry measurements into plasma density control (gas feedback control) as well machine protection systems (neutral beam injection heating safety interlocks). The addition was used successfully during 2014 Campaign is envisaged that will operate routinely from 2015 campaign...
An overview of the preliminary design ITER plasma control system (PCS) is described here, which focusses on needs for 1st and early operation in hydrogen/helium (H/He) up to a current 15 MA with moderate auxiliary heating power low confinement mode (L-mode). Candidate schemes basic magnetic control, including divertor kinetic electron density gas puffing pellet injection, were developed. Commissioning systems included as well support functions stray field topology real-time boundary...