A5016222208- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Nuclear Engineering Thermal-Hydraulics
- Plasma Diagnostics and Applications
- Anomaly Detection Techniques and Applications
- Magnetic Field Sensors Techniques
- Physics of Superconductivity and Magnetism
- Industrial Engineering and Technologies
- Atomic and Subatomic Physics Research
- Network Security and Intrusion Detection
- Oil and Gas Production Techniques
- Fault Detection and Control Systems
- Optimization and Search Problems
- Solar and Space Plasma Dynamics
- Engineering and Environmental Studies
- Electric Power Systems and Control
- Modular Robots and Swarm Intelligence
- Plasma and Flow Control in Aerodynamics
- Advanced Measurement and Metrology Techniques
- Mechanical Systems and Engineering
Culham Centre for Fusion Energy
2007-2024
Culham Science Centre
2014-2024
United Kingdom Atomic Energy Authority
1994-2024
Moscow Institute of Physics and Technology
2023
Bratsk State University
2021
Royal Military Academy
2020
Moscow State Technological University
2014
Japan Atomic Energy Agency
2013
ITER
2011
University of Lisbon
2010
Recent experiments on JET have shown that type-I edge localized modes (ELMs) can be controlled by the application of static low n = 1 external magnetic perturbation fields produced four error field correction coils (EFCC) mounted far away from plasma between transformer limbs. When an with amplitude a few mT at (the normalized poloidal flux, ?, is larger than 0.95) applied during stationary phase ELMy H-mode plasma, ELM frequency rises ~30?Hz up to ~120?Hz. The energy loss per total stored...
This paper describes progress achieved since 2007 in understanding disruptions tokamaks, when the effect of plasma current sharing with wall was introduced into theory. As a result, toroidal asymmetry measurements during vertical disruption event (VDE) on Joint European Torus explained. A new kind equilibria and mode coupling theory, which can explain duration external kink 1/1 VDE. The presents first results numerical simulations using free boundary model, relevant to disruptions.
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...
Abstract In this paper, we revisit the physics of mitigated and unmitigated vertical displacement events (VDEs) present a summary modelling efforts code capabilities. While 3D MHD simulations VDEs for AUG JET are now approaching realistic plasma parameters (e.g. resistivity) getting closer to experimental observations CQ times vessel forces), time scales ITER (∼500 ms) still out computational reach. Therefore, re-scaling parameters, model simplifications or demanding matrix pre-conditioning...
A key feature of disruptions during vertical displacement events, discovered in JET 1996, is the toroidal variation measured plasma current Ip, i.e. asymmetries, lasting for almost entire quench. The unique magnetic diagnostics at (full set poloidal coils and saddle loops recorded either from two toroidally opposite or four orthogonal locations) allow a comprehensive analysis asymmetrical with large scale database. This paper presents an 4854 over 18 year period that includes both carbon (C)...
Abstract The amplitude of locked instabilities, likely magnetic islands, seen as precursors to disruptions has been studied using data from the JET, ASDEX Upgrade and COMPASS tokamaks. It was found that thermal quench, often initiates disruption, is triggered when reached a distinct level. This information can be used determine thresholds for simple disruption prediction schemes. measured in part depends on distance perturbation measurement coils. Hence threshold mode location (i.e. rational...
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 pre-thermal quench (pre-TQ) dynamics of a pure deuterium ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> ) shattered pellet injection (SPI) into <mml:mn>3</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mi>MA</mml:mi> / <mml:mn>7</mml:mn> <mml:mi>MJ</mml:mi> JET H-mode plasma is studied via 3D non-linear MHD modelling with the JOREK code....
Recent progress in experimental and theoretical studies of edge localized mode (ELM) physics is reviewed for the reactor relevant plasma regimes, namely high confinement that is, H-modes advanced scenarios.
Asymmetrical disruptions may occur during ITER operation and they be accompanied by large sideways forces rotation of the asymmetry. This is particular concern because resonance rotating asymmetry with natural frequencies vacuum vessel (and other in-vessel components) could lead to dynamic amplification forces. A significant fraction non-mitigated JET have toroidally asymmetric currents that flow partially inside plasma surrounding ('wall'). The toroidal asymmetries (otherwise known as...
The operational domain for active control of type-I edge localized modes (ELMs) with an n = 1 external magnetic perturbation field induced by the ex-vessel error correction coils on JET has been developed towards more ITER-relevant regimes high plasma triangularity, up to 0.45, normalized beta, 3.0, current 2.0 MA and q95 varied between 3.0 4.8. results ELM mitigation in triangularity plasmas show that frequency ELMs increased a factor 4 during application fields, while energy loss per ELM,...
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:...
Advanced scenario plasmas must often be run at low densities and high power, leading to hot edge temperatures consequent power handling issues plasma - surface interaction zones. Experiments ...
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...
Abstract 3D non-linear magnetohydrodynamic simulations of a disruption triggered by massive injection argon gas in JET are performed with the JOREK code. The key role thermal drive m = 2, n 1 tearing mode (i.e. from helical cooling inside island) process is highlighted varying amplitude and position source across simulations, also during simulation. In cases where this persists spite development magnetic stochasticity, which favoured moving an ad hoc way plasma edge into 2/1 island at some...
The paper presents results on the use of resonant field amplification for experimental probing stability and β-limits (β is ratio plasma pressure to magnetic pressure) in JET. It found that an externally applied helical strongly enhanced when exceeds ideal no-wall limit or approaches proximity other marginally stable (i.e. current-driven) modes. This effect known as (RFA) was used systematic different advanced regimes application this technique JET discussed RFA measurements are presented...
The paper deals with radiation resistant sensors and their associated measuring instrumentation developed in the course of R D activities carried out framework an international collaboration. first trial tests three-dimensional (3D) probes Hall have been performed European tokamaks TORE SUPRA (2004) JET (2005). Later 2009 six sets 3D were installed now continue to operate. statistical analysis 2014 on basis database demonstrated stable long term operation all 18 probes. results measurements...
Halo currents generated during unmitigated tokamak disruptions are known to develop rotating asymmetric features that of great concern ITER because they can dynamically amplify the mechanical stresses on machine. This paper presents a multi-machine analysis these phenomena. More specifically, data from C-Mod, NSTX, ASDEX Upgrade, DIII-D, and JET used empirical scalings three key quantities: (1) machine-specific minimum current quench time, ; (2) halo rotation duration, (3) average frequency,...
Abstract Disruptions lead to a rapid loss of thermal and magnetic energy can cause large heat loads, mechanical forces, the excitation beam relativistic runaway electrons. The operation tokamaks at high plasma current requires use mitigation system limit such detrimental effects. Mitigation techniques rely mainly on injection amount impurities radiate majority energies. Heat loads electro-magnetic (EM) forces as well their toroidal asymmetries be greatly reduced by measures. In this paper,...
The gyrokinetic toroidal code (GTC) has been used to study Alfvén eigenmodes (TAEs) in high-performance plasmas. Experiments performed at the Joint European Torus (JET), where TAEs were driven by energetic particles arising from neutral beams, ion cyclotron resonant heating, and resonantly excited dedicated external antennas, have simulated. Modes populations of are observed, matching TAE frequency seen with magnetic probes JET experiments. A synthetic antenna, composed one two neighboring...