C. F. Maggi
A5004328482- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Electrostatic Discharge in Electronics
- Nuclear Materials and Properties
- Meteorological Phenomena and Simulations
- Atomic and Subatomic Physics Research
- Computational Fluid Dynamics and Aerodynamics
- Advanced Chemical Physics Studies
- Evacuation and Crowd Dynamics
- Metallurgical Processes and Thermodynamics
- Quantum, superfluid, helium dynamics
- Advanced Data Storage Technologies
- Geophysics and Gravity Measurements
- Nuclear Engineering Thermal-Hydraulics
Culham Centre for Fusion Energy
2015-2024
United Kingdom Atomic Energy Authority
2018-2024
Culham Science Centre
2015-2024
Max Planck Society
2008-2019
Max Planck Institute for Plasma Physics
2008-2019
Fusion Academy
2019
Fusion (United States)
2019
KTH Royal Institute of Technology
2019
Czech Academy of Sciences, Institute of Plasma Physics
2019
University of York
2019
Abstract In 2021 JET exploited its unique capabilities to operate with T and D–T fuel an ITER-like Be/W wall (JET-ILW). This second major campaign (DTE2), after DTE1 in 1997, represented the culmination of a series enhancements—new fusion diagnostics, new injection capabilities, refurbishment plant, increased auxiliary heating, in-vessel calibration 14 MeV neutron yield monitors—as well as significant advances plasma theory modelling community. DTE2 was complemented by sequence isotope...
The experimental characteristics of divertor detachment in the JET tokamak with Mark I pumped are presented for ohmic, L mode and ELMy H experiments main emphasis on discharges deuterium fuelling only. range over which is observed various regimes, as well influence configuration, direction toroidal field, target material active pumping detachment, will be described. characteristics, such existence a considerable electron pressure drop along field lines scrape-off layer (SOL), compatibility...
The tungsten programme in ASDEX Upgrade is pursued towards a full high-Z device. spectroscopic diagnostic of W has been extended and refined the cooling factor re-evaluated. coated surfaces now represent fraction 65% all plasma facing components (24.8 m2). only two major that are not yet strikepoint region lower divertor as well limiters at low field side. While extending surfaces, concentration discharge behaviour have changed gradually pointing to critical issues when operating with wall:...
The pressure at the top of edge transport barrier (or ‘pedestal height’) strongly impacts fusion performance, while large localized modes (ELMs), driven by free energy in pedestal region, can constrain material lifetimes. Accurately predicting height and ELM behavior ITER is an essential element prediction optimization performance. Investigation intermediate wavelength MHD ‘peeling–ballooning’ modes) has led to improved understanding important constraints on mechanism for ELMs. combination...
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...
The dependence of plasma transport and confinement on the main hydrogenic ion isotope mass is fundamental importance for understanding turbulent and, therefore, accurate extrapolations from present tokamak experiments, which typically use a single hydrogen isotope, to burning plasmas such as ITER, will operate in deuterium–tritium mixtures. Knowledge properties edge barrier formation species critical view initial, low-activation phase ITER operations or helium its implications subsequent...
Future fusion reactors require a safe, steady state divertor operation. A possible solution for the power exhaust challenge is detached operation in scenarios with high radiated fractions. The radiation can be increased by seeding impurities, such as N dominant scrape-off-layer radiation, Ne or Ar SOL and pedestal Kr core radiation. Recent experiments on two of all-metal tokamaks, ASDEX Upgrade (AUG) JET, demonstrate fractions fully-detached N, conventional vertical target geometry. For both...
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...
A comparison of the L–H power threshold (Pthr) in JET with all carbon, JET-C, and beryllium/tungsten wall (the ITER-like choice), JET-ILW, has been carried out experiments slow input ramps matched plasma shapes, divertor configuration IP/BT pairs. The low density dependence threshold, namely an increase below a minimum ne,min, which was first observed MkII-GB C subsequently not current MkII-HD geometry, is again JET-ILW. At densities above Pthr reduced by ∼30%, ∼40% when radiation from bulk...
The replacement of the JET carbon wall (C-wall) by a Be/W ITER-like (ILW) has affected plasma energy confinement. To investigate this, experiments have been performed with both C-wall and ILW to vary heating power over wide range for plasmas different shapes.
Abstract In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and between thermal ions fast particles generated by neutral beam injection (NBI) heating or accelerated electromagnetic wave in ion cyclotron range of frequencies (ICRFs). To complement experiments with 50/50 D/T mixtures maximizing reactivity, a scenario dominant non-thermal reactivity has been developed successfully demonstrated during second campaign DTE2, as it was predicted to...
Abstract The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with ITER-like Be/W wall. development started pure Deuterium refinement of current, and toroidal magnetic field choices succeeded solving heat load challenges arising 37 MW injected power ITER like environment, keeping radiation edge core controlled, avoiding MHD instabilities reaching high neutron rates. have re-run Tritium...
In the ASDEX Upgrade tokamak, power deposition structures on divertor target plates during type-I edge localized modes (ELMs) have been investigated by infrared thermography. addition to axisymmetric strike line, several poloidally displaced stripes are resolved, identifying an ELM as a composite of subevents. This pattern is interpreted being signature helical perturbations in low field side non-linear evolution. Based this observation, related magnetic perturbation midplane can be derived...
ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It found that large He content in plasma, resulting from DC glow discharges for conditioning, leads a confinement reduction. After change D inter-shot quickly dropped and, parallel, usual H-Mode with H factors close one achieved. initial conditioning phase, oxygen concentrations...
After completion of the tungsten coating all plasma facing components, ASDEX Upgrade has been operated without boronization for 1 1/2 experimental campaigns. This allowed study fuel retention under conditions relatively low D co-deposition with low- Z impurities as well operational space a full-tungsten device unfavourable condition high intrinsic impurity level. Restrictions in operation were caused by central accumulation combination density peaking, resulting H–L backtransitions induced...
In 2008, experiments have been carried out in ASDEX Upgrade to compare Hmode power threshold and confinement time helium deuterium.A scan magnetic field a wide density variation indicate that the two gases is very similar.The dependence of exhibits clear minimum.Confinement about 30% lower than deuterium, mainly due reduction ion caused by Z=2 helium.
Recent developments in theory-based modelling of core heavy impurity transport are presented, and shown to be necessary for quantitative description present experiments JET ASDEX Upgrade. The treatment impurities is complicated by their large mass charge, which result a strong response plasma rotation or any small background electrostatic field the plasma, such as that generated anisotropic external heating. These forces lead poloidal asymmetries density, have recently been added numerical...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation M. N. A. Beurskens, T. H. Osborne, P. Schneider, E. Wolfrum, L. Frassinetti, R. Groebner, Lomas, I. Nunes, S. Saarelma, Scannell, B. Snyder, D. Zarzoso, Balboa, Bray, Brix, J. Flanagan, C. Giroud, Giovannozzi, Kempenaars, Loarte, de la Luna, G. Maddison, F. Maggi, McDonald, Pasqualotto, Saibene, Sartori, Emilia...
Abstract New experiments in 2013–2014 have investigated the physics responsible for decrease H-mode pedestal confinement observed initial phase of JET-ILW operation (2012 Experimental Campaigns). The effects plasma triangularity, global beta and neutrals on stability been systematically. pedestals is analysed framework peeling–ballooning model assumptions predictive code EPED. Low D content plasma, achieved either by low 2 gas injection rates or divertor configurations with optimum pumping,...
Abstract Ion cyclotron resonance frequency (ICRF) heating has been an essential component in the development of high power H-mode scenarios Jet European Torus ITER-like wall (JET-ILW). The ICRF performance was improved by enhancing antenna-plasma coupling with dedicated main chamber gas injection, including preliminary minimization RF-induced plasma-wall interactions, while RF where optimized for core impurity screening terms ion position and minority hydrogen concentration. impact on...
In the recent JET experimental campaigns with new ITER-like wall (JET-ILW), major progress has been achieved in characterization and operation of H-mode regime metallic environments: (i) plasma breakdown at first attempt X-point L-mode recovered a few days operation; (ii) stationary stable type-I ELMy H-modes βN ∼ 1.4 have low high triangularity shape plasmas are showing that their operational domain H = 1 is significantly reduced JET-ILW mainly because need to inject large amount gas (above...
High spatial resolution Doppler backscattering measurements in JET have enabled new insights into the development of edge Er. We observe fine-scale structures Er well with a wave number krρi≈0.4-0.8, consistent stationary zonal flows, characteristics which vary density. The flow amplitude and wavelength both decrease local collisionality, such that E×B shear increases. Above minimum L-H transition power threshold dependence on density, flows are present during L mode disappear following...
Type I ELMy H-mode operation in JET with the ITER-like Be/W wall (JET-ILW) generally occurs at lower pedestal pressures compared to those full carbon (JET-C). The density is similar but temperature where type ELMs occur reduced and below so-called critical I–type III transition reported JET-C experiments. Furthermore, confinement factor H98(y,2) baseline plasmas JET-ILW low power fractions Ploss/Pthr,08 < 2 (where Ploss (Pin − dW/dt), Pthr,08 L–H threshold from Martin et al 2008 (J. Phys....
This paper compares the gyrokinetic instabilities and transport in two representative JET pedestals, one (pulse 78697) from configuration with a carbon wall (C) another 92432) after installation of JET's ITER-like Wall (ILW).The discharges were selected for comparison JET-ILW JET-C good confinement at high current (3 MA, corresponding also to low ρ * ) retain distinguishing features JET-ILW, notably, decreased pedestal top temperature JET-ILW.A profiles heating power reveals stark...
Abstract We present the results of GENE gyrokinetic calculations based on a series JET–ITER-like-wall (ILW) type I ELMy H-mode discharges operating with similar experimental inputs but at different levels power and gas fuelling. show that turbulence due to electron-temperature-gradient (ETGs) modes produces significant amount heat flux in four JET–ILW discharges, and, when combined neoclassical simulations, is able reproduce for two low pulses. The simulations plausibly high-gas fluxes as...