A5078923957- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Advanced Data Storage Technologies
- Nuclear Materials and Properties
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Electrostatic Discharge in Electronics
- Nuclear Engineering Thermal-Hydraulics
- Atomic and Molecular Physics
- High-Energy Particle Collisions Research
- Pulsed Power Technology Applications
- Vacuum and Plasma Arcs
- Particle physics theoretical and experimental studies
- Distributed and Parallel Computing Systems
- Parallel Computing and Optimization Techniques
- Plasma and Flow Control in Aerodynamics
- Hydrogen Storage and Materials
- Dust and Plasma Wave Phenomena
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2025
CEA Cadarache
2016-2025
United Kingdom Atomic Energy Authority
2024
Culham Science Centre
2013-2024
Culham Centre for Fusion Energy
2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2010-2021
Royal Military Academy
2020
Max Planck Institute for Plasma Physics
2015-2016
Max Planck Society
2016
Centre National de la Recherche Scientifique
2012-2015
JOREK is a massively parallel fully implicit non-linear extended MHD code for realistic tokamak X-point plasmas. It has become widely used versatile studying large-scale plasma instabilities and their control developed in an international community. This article gives comprehensive overview of the physics models implemented, numerical methods applied solving equations studies performed with code. A dedicated section highlights some verification work done hierarchy different available...
Disruption mitigation is mandatory for ITER in order to reduce forces, mitigate heat loads during the thermal quench and avoid runaway electrons (REs). A fast disruption valve has been installed at JET study by massive gas injection. Different species amounts have investigated with respect timescales efficiency. We discuss of halo currents as well sideways forces vertical displacement events, increased energy dissipation through radiation, which could arise asymmetric radiation suppression REs.
In the European fusion roadmap, ITER is followed by a demonstration power reactor (DEMO), for which conceptual design under development. This paper reports first results of coherent effort to develop relevant physics knowledge that (DEMO Physics Basis), carried out experts. The program currently includes investigations in areas scenario modeling, transport, MHD, heating & current drive, fast particles, plasma wall interaction and disruptions.
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...
For the first time it is experimentally demonstrated on JET tokamak that a combination of low impurity concentration bulk plasma and large magnetohydrodynamic instabilities able to suppress relativistic electron beams without measurable heat loads onto facing components. Magnetohydrodynamic simulations instability modeling postinstability confirm prompt loss runaways absence regeneration during final current collapse. These surprising findings motivate new approach dissipate runaway...
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...
Abstract This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that low density ( n e ) companion plasma was required to achieve large MHD instability, which expelled confined REs over wetted area allowed conversion magnetic energy radiation. Control achieved via neutral pressure regulation agnostic material injection method. The recombination found be dependent impurity species, quantity RE...
Disruptions are a critical issue for ITER because of the high thermal and magnetic energies that released on short timescales, which results in extreme forces heat loads. The choice material plasma-facing components (PFCs) can have significant impact loads arise during disruption. With ITER-like wall (ILW) JET made beryllium main chamber tungsten divertor, finding is low fraction radiation. This has dropped significantly with ILW from 50–100% total energy being dissipated disruptions CFC...
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...
In October 2014, JET completed a scoping study involving high power scenario development in preparation for DT along with other experiments critical ITER.These have involved intentional and unintentional melt damage both to bulk beryllium main chamber tiles divertor tiles.This paper provides an overview of the findings concern machine protection ITER, illustrating each case resolution images taken by remote handling or after removal from machine.The upper dump plate some been repeatedly...
The new full-metal ITER-like wall (ILW) at JET was found to have a profound impact on the physics of disruptions. main difference is significantly lower fraction (by up factor 5) energy radiated during disruption process, yielding higher plasma temperatures after thermal quench and thus longer current times. Thus, larger total conducted resulting in heat loads. Active mitigation by means massive gas injection became necessity avoid beryllium melting already moderate levels magnetic (i.e....
In order to preserve the integrity of large tokamaks such as ITER, number disruptions has be limited. JET operated previously with a low frequency (i.e., disruption rate) 3.4% [P. C. de Vries et al., Nucl. Fusion 51, 053018 (2011)]. The start operations new full-metal ITER-like wall at showed marked rise in rate 10%. A full survey was carried out identify root causes, chain-of-events and classifying each disruption, similar previous analysis for carbon-wall operations. It improvements made...
Abstract A series of experiments have been executed at JET to assess the efficacy newly installed shattered pellet injection (SPI) system in mitigating effects disruptions. Issues, important for ITER disruption mitigation system, such as thermal load mitigation, avoidance runaway electron (RE) formation, radiation asymmetries during quench electromagnetic control and RE energy dissipation addressed over a large parameter range. The efficiency has examined various SPI strategies. paper...
Disruptions are a major threat for future tokamaks, including ITER. Disruption-generated heat loads, electromagnetic forces and runaway electrons will not be tolerable next-generation devices. Massive noble gas injection is foreseen as standard mitigation system these tokamaks. Disruption experiments have been carried out on Tore Supra to study various scenarios investigate jet penetration mixing. Comparisons of different gases (He, Ne, Ar, He/Ar mixture) amounts (from 5 500 Pa m 3 ) were...
Relativistic electron (RE) beams at high current density (low safety factor, qa) yet very low free-electron accessed with D2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate RE beam. In JET, this technique has enabled termination of MA-level currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway achieve mitigation collisional dissipation. Benign is explained by two...
Abstract The reference ion cyclotron resonance frequency (ICRF) heating schemes for ITER deuterium–tritium (D-T) plasmas at the full magnetic field of 5.3 T are second harmonic and 3 He minority heating. wave-particle location these coincide central a wave 53 MHz T. Experiments have been carried out in major D-T campaign (DTE2) JET, its prior D campaigns, to integrate ICRF scenarios JET high-performance compare their performance with commonly used hydrogen (H) In 50:50 D:T plasmas, up 35% 5%...
Abstract Plasma disruptions present a significant challenge to the viability of fusion energy production in tokamak reactors. Among disruption mitigation techniques, shattered pellet injection (SPI) has emerged as promising approach. The results presented this paper show novel findings impact nitrogen and neon seeding on sequence following SPI Joint European Torus (JET). This study exposes an order magnitude reduction pre-thermal quench duration for highly seeded plasmas pure deuterium SPI,...
Abstract We present a model for the particle balance in post-disruption runaway electron plateau phase of tokamak discharge. The is constructed with help of, and applied to, experimental data from TCV discharges investigating so-called ``low-Z benign termination'' mitigation scheme. In termination scheme, free density first reduced order subsequently induced MHD instability to grow rapidly spread electrons widely across wall. show that observed non-monotonic dependence measured neutral...
A demonstration power plant (DEMO) will be the next step for fusion energy following ITER. Some of key design questions can addressed by simulations using system codes. System codes aim to model whole with all its subsystems and identify impact their interactions on choices. The SYCOMORE code is a modular developed address relevant tokamak reactor design. being within European Integrated Tokamak Modelling framework provides global view (technology physics) plant. It includes modules plasma...
JOREK 3D non-linear MHD simulations of a D2 Massive Gas Injection (MGI) triggered disruption in JET are presented and compared detail to experimental data. The MGI creates an overdensity that rapidly expands the direction parallel magnetic field. It also causes growth islands (m/n=2/1 3/2 mainly) seeds 1/1 internal kink mode. O-points all island chains (including 1/1) located front MGI, consistently with observations. A burst activity peak plasma current take place at same time as...
Tokamak operation with W PFCs is associated specific challenges for impurity control, which may be particularly demanding in the transition from stationary H-mode to L-mode. To address contr ...
Abstract A runaway electron (RE) fluid model is used to perform non-linear magnetohydrodynamic simulations of a relativistic beam termination event in JET. The case considered that post-disruption low density cold plasma the plateau phase, wherein high-Z impurities have been largely flushed out via deuterium second injection (Shot:95135). Details experiment are found separate publications. Our studies reveal combination and hollow current profile which confirmed by experimental causes fast...
Abstract The consequences of tungsten (W) melting on divertor lifetime and plasma operation are high priority issues for ITER. Sustained controlled W-melting experiment has been achieved the first time in WEST a poloidal sharp leading edge an actively cooled ITER-like facing unit (PFU). A series dedicated power steady state discharges were performed to reach point tungsten. was exposed parallel heat flux about 100 MW.m −2 up 5 s providing melt phase 2 without noticeable impact (radiated...