A5034960384- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Meteorological Phenomena and Simulations
- Advanced Sensor Technologies Research
- Radiation Detection and Scintillator Technologies
- Geophysics and Gravity Measurements
- Ion-surface interactions and analysis
- Reinforcement Learning in Robotics
- Metal and Thin Film Mechanics
- High-Energy Particle Collisions Research
- Dust and Plasma Wave Phenomena
- Electrohydrodynamics and Fluid Dynamics
- Artificial Intelligence in Games
- Human Pose and Action Recognition
Culham Centre for Fusion Energy
2011-2025
Culham Science Centre
2015-2025
United Kingdom Atomic Energy Authority
2011-2024
Max Planck Institute for Plasma Physics
1998-2024
TU Dortmund University
2022
Royal Military Academy
2020
Fusion (United States)
2019
Fusion Academy
2019
Max Planck Society
1998-2018
Max Planck Innovation
2007
Access conditions for full suppression of Edge Localised Modes (ELMs) by Magnetic Perturbations (MP) in low density high confinement mode (H-mode) plasmas are studied the ASDEX Upgrade tokamak. The main empirical requirements ELM our experiments are: 1. poloidal spectrum MP must be aligned best plasma response from weakly stable kink-modes, which amplify perturbation, 2. edge below a critical value, $3.3 \times 10^{19}$~m$^{-3}$. collisionality is range $\nu^*_i = 0.15-0.42$ (ions) and...
The programme to design plasma scenarios for the Spherical Tokamak Energy Production (STEP), a reactor concept aiming at net electricity production, seeks exploit inherent advantages of spherical tokamak (ST) while making conservative assumptions about performance. This approach is motivated by large gap between present-day STs and future burning plasmas based on this concept. It concluded that exhaust in such device most likely be manageable double null (DN) configuration, high core...
Abstract STEP is a spherical tokamak prototype power plant that being designed to demonstrate net electric power. The design phase involves the exploitation of plasma models optimise fusion performance subject satisfying various physics and engineering constraints. A modelling workflow, including integrated core modelling, MHD stability analysis, SOL pedestal coil set free boundary equilibrium solvers, whole design, has been developed specify parameters develop viable scenarios. model JETTO...
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...
Experiments have been performed on MAST using internal (n = 3) resonant magnetic perturbation (RMP) coils. The application of the RMPs to L-mode discharges has shown a clear density pump-out when field line pitch angle at low-field side plasma is sufficiently well aligned with applied field. before L–H transition increases power required achieve H-mode by least 30%. In type I ELMing discharges, particular value q95, ELM frequency can be increased factor 5 RMPs. This effect ELMs and not...
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...
The development of small Edge Localized Mode (ELM) scenarios is important in order to reduce the strain on plasma facing components.One such scenario can be found at high densities, highly shaped, close double-null plasmas ASDEX Upgrade, showing ELMs characterized by a frequency f ELM > 300Hz and low power loss.Changing from gas fuelling pellet results edge profiles which collisionality pedestal top separatrix are decoupled.While values remain unchanged, only phases with scrape-off layer...
One of our grand challenges towards fusion energy is the achievement a high-performance plasma core coupled to boundary solution. The high confinement mode (H-mode) provides such due build-up an edge transport barrier leading pedestal. However, it usually features type-I localized modes (ELMs) which pose threat for long-duration operation in future devices as they induce large fluences onto facing components and typically are projected damage first wall. For devices, integration stationary...
Tokamak operational regimes with small edge localized modes (ELMs) could be a solution to the problem of large transient heat loads in fusion reactors. A ballooning mode near last closed flux surface governed by pressure gradient and magnetic shear there has been proposed for ELMs. In this Letter, we experimentally investigate several stabilizing effects present linear ideal simulations that indeed develop ballooninglike fluctuations connect them nonlinear resistive simulations. The...
Success of the UK’s Spherical Tokamak for Energy Production (STEP) programme requires a robust plasma control system. This system has to guide from initiation burning phase, maintain it there, produce desired fusion power duration and then terminate safely. be done in challenging environment with limited sensors without overloading plasma-facing components. The parameters operational regime STEP prototype will very different tokamaks, which are presently operation. During burn,...
STEP is a spherical tokamak prototype power plant that being designed to demonstrate net electric power. The design phase involves the exploitation of plasma models optimise fusion performance subject satisfying various physics and engineering constraints. A modelling workflow, including integrated core modelling, MHD stability analysis, SOL pedestal coil set free boundary equilibrium solvers, whole design, has been developed specify parameters develop viable scenarios. model JETTO used...
2019) 076038 (17pp) (mainly ETG and ITG) by 50%.This suggests that, in these plasmas, the increase turbulent transport due to outward shift of density might play an important role decrease pedestal performance.
This paper presents a description of the spatial and temporal structure edge-localized modes (ELMs) observed in MAST tokamak. Filamentary enhancements visible light are on photographic images plasma obtained during ELMs. Comparisons with simulations show that these filaments consistent following field lines at outboard edge plasma. The toroidal mode number has been extracted from study discrete peaks ion saturation current recorded by mid-plane reciprocating probe. A time delay respect to...
A combination of recently installed state-of-the-art imaging and profile diagnostics, together with established plasma simulation codes, are providing for the first time on Mega Ampère Spherical Tokamak (MAST) tools required studying confinement transport, from core through to edge scrape-off-layer (SOL). The H-mode transport barrier is now routinely turned off using a poloidally localized fuelling fine balancing X-points. Theory, supported by experiment, indicates that radial electric field...
Edge localized mode (ELM) characteristics in a large spherical tokamak (ST) with significant auxiliary heating are explored. High confinement is achieved mega ampere (MAST) at low ELM frequencies even though the ELMs exhibit many type III characteristics. These associated reduction pedestal density but no change temperature or profile, indicating that energy convected from region into scrape-off layer. Power to targets during an arrives predominantly field outboard side. effluxes observed up...
Studies of the pedestal characteristics and quantities determining edge-localized mode (ELM) energy losses in MAST are presented. High temperature plasmas have been achieved which collisionalities one order magnitude lower than previous results . A stability analysis performed on these shows them to be near ballooning limit. The fraction released by an ELM as a function collisionality is consistent with data from other devices. evolution filamentary structures observed during ELMs has...
The developments of advanced tokamak scenarios as well the employment a new neutral beam injection (NBI) source with higher power and energy up to ≈65 keV have significantly broadened frequency range variety Alfvén eigenmodes (AEs) excited by super-Alfvénic NBI on spherical MAST. During recent experiments MAST, several distinct classes beam-driven AEs been identified, different modes being most unstable in MAST scenarios. In discharges elevated monotonic q ( r )-profiles ⩾3 MW, chirping...
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...
The high-k () wavenumber spectrum of density fluctuations has been measured for the first time in MAST (Lloyd et al 2003 Nucl. Fusion 43 1665). This was accomplished with implementation Doppler backscattering (DBS) core measurements a spherical tokamak. DBS become well-established and versatile diagnostic technique measurement intermediate- k (, higher) flows magnetically confined fusion experiments. Previous implementations have standard, large aspect ratio tokamaks. A novel two-dimensional...
Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle role plasma fueling shape for onset small ELM regimes. On both devices, regimes with high confinement are achieved if only two conditions fulfilled at same time. Firstly, density separatrix must be large enough (), leading pressure profile flattening separatrix, which stabilizes type-I ELMs. Secondly, magnetic configuration close double null (DN), reduction shear in...
Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat particle loads on wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research ASDEX Upgrade (AUG), MAST TCV. This multi-machine approach within EU-MST, covering wide parameter range, instrumental progress in field, as ITER DEMO core/pedestal SOL parameters are not achievable simultaneously present day devices. A two prong adopted. On one...
Abstract The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance physics base of ITER and DEMO. Here, full tungsten wall is a key asset for extrapolating future devices. high overall heating power, flexible mix comprehensive diagnostic set allows studies ranging from mimicking scrape-off-layer divertor conditions DEMO at density fully non-inductive operation ( q 95 = 5.5, ) low density. Higher installed electron cyclotron...
The mega amp spherical tokamak (MAST) was a low aspect ratio device (R/a = 0.85/0.65 ~ 1.3) with similar poloidal cross-section to other medium-size tokamaks. physics programme concentrates on addressing key issues for the operation of ITER, design DEMO and future tokamaks by utilising high resolution diagnostic measurements closely coupled theory modelling significantly advance our understanding. An empirical scaling energy confinement time that favours higher power, lower collisionality...