A5071536568- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Nuclear Materials and Properties
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Magnetic Field Sensors Techniques
- Metallurgical Processes and Thermodynamics
- Atomic and Molecular Physics
- Nuclear Engineering Thermal-Hydraulics
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Advanced materials and composites
- Mineral Processing and Grinding
- Dust and Plasma Wave Phenomena
- Thermal Analysis in Power Transmission
- High voltage insulation and dielectric phenomena
- Advanced Fiber Optic Sensors
- Geomagnetism and Paleomagnetism Studies
- Gas Dynamics and Kinetic Theory
- Radiation Effects in Electronics
- High-Energy Particle Collisions Research
Fusion Academy
2024
Boston Fusion (United States)
2017-2024
Princeton Plasma Physics Laboratory
2017-2020
CEA Cadarache
2017-2020
Zhejiang University
2020
Institute of Ionized Gas
2017-2020
Culham Centre for Fusion Energy
2007-2017
Culham Science Centre
2008-2017
United Kingdom Atomic Energy Authority
2002-2014
Japan Atomic Energy Agency
2013
Progress in the area of MHD stability and disruptions, since publication 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137–2664), is reviewed. Recent theoretical experimental research has made important advances both understanding control tokamak plasmas. Sawteeth are anticipated baseline ELMy H-mode scenario, but tools exist to avoid or them through localized current drive fast ion generation. Active other instabilities will most likely be also required ITER. Extrapolation from...
This paper reports the successful installation of JET ITER-like wall and realization its technical objectives. It also presents an overview planned experimental programme which has been optimized to exploit new other enhancements in 2011/12.
Abstract The SPARC tokamak project, currently in engineering design, aims to achieve breakeven and burning plasma conditions a compact device, thanks new developments high-temperature superconductor technology. With magnetic field of 12.2 T on axis 8.7 MA current, is predicted produce 140 MW fusion power with gain Q ≈ 11, providing ample margin respect its mission > 2. All systems are being designed this landmark discharge, thus enabling the study physics operations reactor relevant pave...
A survey has been carried out into the causes of all 2309 disruptions over last decade JET operations. The aim this was to obtain a complete picture possible disruption causes, in order devise better strategies prevent or mitigate their impact. analysis allows effort avoid be more efficient and effective. As expected, highly complex pattern chain events that led emerged. It found majority had technical root cause, for example due control errors, operator mistakes. These bring random,...
Combined analysis of divertor thermocouple and IR camera measurements during JET disruptions can provide valuable information on the distribution energy loads, even if stored plasmas is small compared to that foreseen for next-generation tokamaks. Typically collected at represents a fraction pre-disruption plasma energy; this consistent with high level radiation observed part magnetic being transferred plasma-coupled conductors.
New experimental results on transient loads during ELMs and disruptions in present divertor tokamaks are described used to carry out a extrapolation ITER reference conditions draw consequences for its operation. In particular, the achievement of low energy/convective type I edge localized modes (ELMs) ITER-like plasma seems only way obtain which may be compatible with an acceptable erosion lifetime facing components (PFCs) ITER. Power disruptions, contrary, seem lead most cases because...
A multi-device database of disruption characteristics has been developed under the auspices International Tokamak Physics Activity magneto-hydrodynamics topical group. The purpose this ITPA (IDDB) is to find commonalities between and mitigation in a wide variety tokamaks order elucidate physics underlying tokamak disruptions extrapolate toward much larger devices, such as ITER future burning plasma devices. In contrast previous smaller data collation efforts, IDDB aims provide significant...
Plasma disruptions affect plasma-facing and structural components of tokamaks due to electromechanical forces, thermal loads generation high energy runaway electrons (REs). Asymmetries in poloidal halo toroidal plasma current can now be routinely measured four positions 90° apart. Their assessment is used validate the design ITER vessel support system its in-vessel components. The challenge disruption comes from both short duration over which a large has lost potential for asymmetries. focus...
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)...
The magnetic energy balance and flows for plasma disruptions in which runaway plateau plasmas are formed terminated at JET has been analysed compared with that of runaway-free disruptions. analysis shows the loss processes during termination qualitatively different from those a disruption because pre-existence population first case. As consequence, significant fraction is directly converted into electron kinetic phase. This leads to fluxes being deposited by electrons onto in-vessel...
In this paper we analyse and discuss the thermal energy loss dynamics before during JET disruptions that occurred between 2002 2004 in discharges which reached >4.5 MJ of energy. We observe slow transients with diamagnetic loops fast ones electron cyclotron emission soft x-ray diagnostics. For most disruption types JET, plasma at time quench is substantially less than full performance plasma, typically range 10–50% depending on conditions type. The exceptions to observation are plasmas a...
This paper presents an overview of the status and relevant technical issues for ITER-like Wall Project with emphasis on progress since 11th International Workshop Plasma-Facing Materials Components Fusion Applications.
In JET, during some vertical displacement events (VDEs), the plasma current and position are toroidally asymmetric. These referred to as asymmetric VDEs (AVDEs). Analysis of interactions among carrying systems reveals that repelling force between vessel is little significance in events, even if it main symmetric force. The sideways acting on shown be due mainly interaction with toroidal field circulation currents wall. path then calculated analytically for a simplified geometry used together...
The halo current detection system in JET was refurbished 2001. collected data confirm previous results, obtained with a smaller number of sensors, and are consistent the ITER assumptions. An analysis recent disruptions shows that local density is linked to average plasma quench rate (the slower disruption, larger load), rather than current. largest densities more likely occur when equilibrium boundary safety factor low it decreases critical value, close 1, during disruption. fractions found...
The poloidal distribution of the halo current density on top dump plate in JET can now be measured thanks to a new set Rogowskii coils. These are first measurements able offer an insight width interaction with wall. Therefore they both validation assumption made for disruption design criteria and one additional point extrapolation expected width, hence (and related local electro-mechanical loads in-vessel components) ITER. During upward events, is consistent total current. footprint extends...
The termination of the current and loss runaway electrons following plateau formation during disruptions have been investigated in JET, DIII-D FTU tokamaks. Substantial conversion magnetic energy into kinetic energy, up to ∼10 times initial has inferred for slowest terminations. Both modelling experiment suggest that, present devices, efficiency is determined a great extent by characteristic time, τdiff, resistive time residual ohmic plasma after disruption, τres, increasing with ratio...
Ion cyclotron resonance frequencies (ICRF) mode conversion has been developed for localized on-axis and off-axis bulk electron heating on the JET tokamak. The fast magnetosonic waves launched from low-field side ICRF antennas are mode-converted to short-wavelength high-field of 3He ion layer in D 4He plasmas subsequently damped electrons. resulting power deposition, measured using modulation, is narrow with a typical full-width at half-maximum ≈30 cm (i.e. about 30% minor radius) total...
The maximum temperature expected in ITER is the region of 40keV and minimum average density approximately 3×1019m−3 also expected. proven capability, convenience, port occupancy LIDAR Thomson scattering approach, demonstrated on JET, makes it an excellent candidate for ITER. Nonetheless, there are formidable design challenges realizing such a diagnostic system. high presents its own problem very large relativistic blueshift scattered spectrum (e.g., λ∕λ0∼0.35 Te=40keV), impacting laser...
For the first time, fast measurements of heat loads on main chamber plasma facing components (about 1 ms time resolution) during disruptions are taken JET. The timescale energy deposition thermal quench is estimated and compared with core collapse measured soft x-ray diagnostic. 3–8 times longer than density limit or radiative disruptions. This factor rather in range 1.5–4 for vertical displacement events. load profiles show substantial broadening power footprint upper dump plate. scrape-off...
The ITER-like wall project in JET aims at an optimal use of the unique features JET, such as beryllium and tritium compatibility, to explore operation within limits ITER materials. A full replacement presently carbon-based first will result surfaces facing plasma being mainly main chamber tungsten divertor. At same time, auxiliary heating power be upgraded allowing access ITER-relevant energy loss densities disruptions edge localized modes. In this way, go from almost indestructible, making...
The chosen materials for plasma facing components the deuterium/tritium phase of ITER are beryllium and tungsten. These have already been widely investigated in various devices like ion beam or electron tests. However, operation this material combination a large tokamak including wall interaction, degradation, erosion mixing has not proven yet.The ITER-like Wall, which recently installed JET, consists bulk tungsten coated CFC divertor tiles as well INCONEL main chamber. experiments JET will...
Abstract During some JET vertical displacement events (VDEs) plasma current and position are found to be toroidally asymmetric. When asymmetries lock, the vessel has been observed move horizontally, consequently strong horizontal forces expected following asymmetries, whether locked or rotating. The cause of is, as already identified in previous works, asymmetric circulation structures. physics mechanism responsible for these currents is instead an open issue it object present analysis. In...
The SPARC tokamak is a high-field, Bt0 ∼12 T, medium-sized, R0 = 1.85 m, that presently under construction in Devens, MA, led by Commonwealth Fusion Systems. It will be used to de-risk the high-field path fusion power plant and demonstrate commercial viability of energy. SPARC’s first campaign plan achieve Qfus > 1 using an ICRF-heated, <10 MW, high current, Ip ∼ 8.5 L-mode fueled D–T gas injection, its second investigate H-mode operations D–D. To facilitate plasma control...