A5026876953- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Atomic and Subatomic Physics Research
- Physics of Superconductivity and Magnetism
- Cold Atom Physics and Bose-Einstein Condensates
- Frequency Control in Power Systems
- Fluid Dynamics and Turbulent Flows
- Underwater Vehicles and Communication Systems
- Astro and Planetary Science
- Nuclear and radioactivity studies
- Real-time simulation and control systems
- Radio Wave Propagation Studies
- Vacuum and Plasma Arcs
- Plasma and Flow Control in Aerodynamics
- Korean Peninsula Historical and Political Studies
- Advanced Sensor Technologies Research
- Satellite Communication Systems
Tokamak Energy (United Kingdom)
2013-2024
Culham Science Centre
2009-2023
United Kingdom Atomic Energy Authority
2000-2023
Oxford Instruments (United Kingdom)
2016
Princeton Plasma Physics Laboratory
2005-2016
Technical University of Denmark
2013-2015
Imperial College London
2014-2015
Culham Centre for Fusion Energy
2005-2014
University of Manchester
2010-2013
United States Naval Research Laboratory
2013
Type-I edge-localized modes (ELMs) have been mitigated at the JET tokamak using a static external $n=1$ perturbation field generated by four error correction coils located far from plasma. During application of ELM frequency increased factor 4 and amplitude ${\mathrm{D}}_{\ensuremath{\alpha}}$ signal decreased. The energy loss per normalized to total stored energy, $\ensuremath{\Delta}W/W$, dropped values below 2%. Transport analyses shows no or only moderate (up 20%) degradation confinement...
The resonant magnetic perturbation (RMP) fields, including the plasma response, are computed within a linear, full toroidal, single-fluid resistive magnetohydrodynamic (MHD) model, and under realistic conditions for MAST ITER. response field is found to be considerably reduced, compared with vacuum produced by coils. This reduction relies strongly on screening effect from toroidal rotation. Computations also quantify three-dimensional (3D) distortions of surface, caused RMP fields. A...
Tokamak Energy Ltd, UK, is developing spherical tokamaks using high temperature superconductor magnets as a possible route to fusion power relatively small devices. We present an overview of the development programme including details enabling technologies, key modelling methods and results, remaining challenges on path compact fusion.
Abstract Ion temperatures of over 100 million degrees Kelvin (8.6 keV) have been produced in the ST40 compact high-field spherical tokamak (ST). excess 5 keV not previously reached any ST and only obtained much larger devices with substantially more plasma heating power. The corresponding fusion triple product is calculated to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>n</mml:mi> <mml:mi>i</mml:mi> <mml:mn>0</mml:mn>...
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...
Remarkable progress has been made in diagnosing energetic particle instabilities on presentday machines and establishing a theoretical framework for describing them.This overview describes the much improved diagnostics of Alfvén modelling tools developed world-wide, discusses interpreting observed phenomena.A multi-machine comparison is presented giving information performance both different plasma conditions outlining expectations ITER based our present knowledge.
Abstract ST40 is a compact, high-field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi mathvariant="normal">T</mml:mi> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mtext>⩽</mml:mtext> <mml:mn>2.1</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>T</mml:mtext> </mml:math> ) spherical tokamak (ST) with mission to expand the physics and technology basis for ST route commercial fusion. The research programme covers...
A proof of principle magnetic feedback stabilization experiment has been carried out to suppress the resistive wall mode (RWM), a branch ideal magnetohydrodynamic (MHD) kink under influence stabilizing wall, on DIII-D tokamak device [Plasma Phys. Controlled Fusion Research (International Atomic Energy Agency, Vienna, 1986), p. 159; Plasmas 1, 1415 (1994)]. The RWM was successfully suppressed and high beta duration above no-wall limit extended more than 50 times flux diffusion time. It...
Recent DIII-D experiments have shown that the growth of n = 1 resistive wall mode (RWM) can be influenced by an external magnetic field applied in closed loop feedback using a six element error correction coil (C coil). The RWM constitutes primary limitation to normalized beta recent advanced tokamak plasma experiments. toroidal rotation plasmas does not seem sufficient completely suppress RWM: very slowly growing (growth rate γ<<1/τw) or saturated is often observed at above no limit and...
Low aspect ratio tokamaks may provide a low cost route to developing magnetic fusion energy and offer simpler more economic reactors. The first test of this concept with hot plasmas has been conducted the Small Tight Aspect Ratio Tokamak (START) experiment now in operation at Culham Laboratory. novel method plasma formation is described observations ratios as 1.3 are presented, indicating high temperature discharges good global stability properties typical tokamak characteristics. This...
This paper considers a fast track to non-energy applications of nuclear fusion that is associated with the ‘fusion for neutrons’ (F4N) paradigm. Being useful product accompanying energy, neutrons are more valuable than energy released in DT reactions and they urgently needed research purposes develop validate modern technologies. In near future neutron yield devices will become significantly larger fission accelerator sources. describes compact tokamak source based on small spherical...
Recently, the TS-3 and TS-4 tokamak merging experiments revealed significant plasma heating during magnetic reconnection. A key question is how where ions electrons are heated Two-dimensional measurements of ion electron temperatures flow made clear that inside current sheet mainly by Ohmic in downstream areas reconnection outflows. The outflow kinetic energy thermalized fast shock formation viscous damping. converts reconnecting field mostly to thermal region whose size much larger than for...
First physics results are presented from MAST (Mega-Amp Spherical Tokamak), one of the new generation purpose built spherical tokamaks (STs) now commencing operation. Some these demonstrate, for first time, novel effects low aspect ratio, example, enhancement resistivity due to neo-classical effects. H-mode is achieved and transition accompanied by a tenfold steepening edge density gradient which may enable successful application electron Bernstein wave heating in STs. Studies halo currents...
In the burning fusion plasmas of next step devices such as ITER (2001 ITER-FEAT Outline Design Report IAEA/ITER EDA/DS/18 (Vienna: IAEA) p 21), majority heating fusing fuel will come from plasma self-heating by born α -particles. Recent advances in theoretical understanding, together with development new diagnostic techniques, make this a timely opportunity to survey role energetic particles and how it projects future devices.
A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magnetic perturbation field on the JET tokamak. Calculation results from momentum transport analysis show that torque induced by a global profile. The maximal value this is at plasma core region (ρ < 0.4) and it about half neutral beam injection torque. calculation shows mainly regime core, but close to transition between 1/ν regimes. neoclassical viscosity (NTV) regimes calculated. magnitude NTV...
The kinetic effects influencing the stability of resistive wall mode (RWM) are investigated by applying a drift code to calculate change in potential energy presence thermal and energetic particles. analysis is carried out for typical JET high-β plasmas. It found that strongest damping RWM arises due resonance with precession motion trapped plasmas also probed using active MHD spectroscopy. frequency spectrum plasma response oscillating externally applied fields has been measured fitted...
Major developments on the Mega Amp Spherical Tokamak (MAST) have enabled important advances in support of ITER and physics basis a spherical tokamak (ST) based component test facility (CTF), as well providing new insight into underlying physics. For example, L–H transition studies benefit from high spatial temporal resolution measurements pedestal profile evolution (temperature, density radial electric field) stability edge current has been inferred motional Stark effect measurements. The...
Mitigation of type-I edge-localized modes (ELMs) was observed with the application an n = 2 field in H-mode plasmas on JET tokamak ITER-like wall (ILW). Several new findings ILW were identified and contrasted to previous carbon (C-wall) results for comparable conditions. Previous high collisionality C-wall saw little or no influence either 1 fields ELMs. However, recent observations show large ELMs a frequency ∼45 Hz replaced by high-frequency (∼200 Hz) small during field. With ILW,...
Different models have been introduced in the stability code MARS-F order to study damping effect on resistive wall modes (RWM) rotating plasmas. Benchmarks of calculations with RWM experiments JET and DIII-D indicate that semi-kinetic model is a good candidate for explaining mechanisms. Based these results, critical rotation speeds required stabilization advanced ITER scenarios are predicted. Active feedback control n = 1 also studied using code.
A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, loop voltage supplied vertical field shaping coils. The Ohmic heating (OH) solenoid not used but a small inboard coil (part coil), providing less than $20%$ total poloidal flux, used. plasma thus obtained had both internal edge transport barriers, with an energy confinement time 1.6 times H-mode scaling, beta...
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,...
The high-beta capability of the spherical tokamak, coupled with a suite world-leading diagnostics on MAST, has facilitated significant improvements in understanding performance-limiting core instabilities high performance plasmas. For instance, newly installed motional Stark effect diagnostic, radial resolution <25 mm, enabled detailed study saturated long-lived modes hybrid scenarios. Similarly, upgraded Thomson scattering system, <10 mm and possibility temporal 1 µs, allowed analysis...
Abstract The non-resonant magnetic braking effect induced by a non-axisymmetric perturbation is investigated on JET and TEXTOR. collisionality dependence of the torque n = 1, where toroidal mode number, generated error field correction coils observed. observed located mainly in plasma core (normalized radius ρ < 0.4) increases with decreasing collisionality. neoclassical viscosity (NTV) collisionless regime modelled using numerical solution bounce-averaged drift kinetic equation....
The three-dimensional plasma boundary displacements induced by applied non-axisymmetric magnetic perturbations have been measured in ASDEX Upgrade, DIII-D, JET, MAST and NSTX. arising from resonant (RMPs) are up to ±5% of the minor radius present-day machines. Good agreement can be found between different experimental measurements a range models—be it vacuum field line tracing, ideal MHD equilibrium modelling, or nonlinear amplification. various with predictions these models is presented,...