A5039361117- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear Materials and Properties
- Dust and Plasma Wave Phenomena
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Nuclear materials and radiation effects
- Aquaculture Nutrition and Growth
- Physics of Superconductivity and Magnetism
- Solar and Space Plasma Dynamics
- Energetic Materials and Combustion
- Radioactive contamination and transfer
- Advanced Frequency and Time Standards
- Nuclear reactor physics and engineering
- Cold Atom Physics and Bose-Einstein Condensates
- Urban Green Space and Health
- Electromagnetic Compatibility and Measurements
- Urban Agriculture and Sustainability
- Electrohydrodynamics and Fluid Dynamics
- Advanced Data Storage Technologies
- Radiation Detection and Scintillator Technologies
Chester Zoo
2023
Fusion for Energy
2011
Culham Centre for Fusion Energy
2000-2009
Culham Science Centre
2000-2009
Japan Atomic Energy Agency
2008
KTH Royal Institute of Technology
2006-2007
United Kingdom Atomic Energy Authority
2000
Science Oxford
1992
University of Oxford
1992
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), highlights similarities with solar eruptions. Taken together, observations presented this provide strong evidence for ELMs being associated a filamentlike structure. These filaments are extended along field line, generated $100\text{ }\ensuremath{\mu}\mathrm{s}$ time scale, erupt from outboard side,...
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...
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 low aspect ratio of the mega amp spherical tokamak (MAST) allows differentiation between different forms H-mode threshold scaling. With optimized fuelling using inboard puffing, and a connected double null divertor (DND) magnetic configuration, power data lie about 1.7 times higher than recent scaling laws. Slight configuration changes, order ion Larmor radius, around DND significantly influence access. confinement in discharges with frequency edge localized modes (ELMs) is generally...
The tight aspect ratios (typically A≈1.4) and low magnetic field of spherical tokamak (ST) plasmas, when combined with densities approaching the Greenwald limit, provide a significant challenge for all currently available auxiliary heating current drive schemes. NBI are difficult to interpret in sub-megampere machines, as order achieve suitable penetration into plasma core, fast ions have be highly suprathermal and, result field, can non-adiabatic (i.e. non-conserving moment µ0). physics...
The DTOKS code, which models dust transport through tokamak plasmas, is described. floating potential and charge of a grain in plasma the fluxes energy to from it are calculated. From this model, temperature can be estimated. A background supplied by standard edge modelling code (B2SOLPS5.0), MAST (the MegaAmp Spherical Tokamak) ITER plasmas presented. We conclude that micron-radius tungsten reach separatrix ITER.
Several improvements to the MAST plant and diagnostics have facilitated new studies advancing physics basis for ITER DEMO, as well future spherical tokamaks (STs). Using increased heating capabilities P NBI ⩽ 3.8 MW H-mode at I p = 1.2 MA was accessed showing that energy confinement on scales more weakly with strongly B t than in IPB98( y , 2) scaling. Measurements of fuel retention shallow pellets extrapolate an particle throughput 70% its original designed total capacity. The anomalous...
This report summarizes Type I edge localized mode (ELM) dynamics measurements from a number of tokamaks, including ASDEX-Upgrade, DIII-D, JET, JT-60U and MAST, with the goal providing guidance insight for development ELM simulation modelling. Several transport mechanisms are conjectured to be responsible transport, convective due filamentary structures ejected pedestal, parallel ergodization or magnetic reconnection turbulent driven by high gradients when radial electric field shear is...
$H$-mode operation has been achieved in high current $({I}_{p}>200\mathrm{kA})$ plasmas the START spherical tokamak for both neutral-beam-injection-heated and Ohmic discharges. The transition to $H$ mode features development of well-defined edge pedestals density temperature, which signifies formation an edge-transport barrier, associated edge-localized modes. Recent at plasma currents exceeding 250 kA shows that these are accompanied by increases energy confinement time. This is first clear...
The paper deals with the interpretation of double-probe characteristics in presence RF voltages. theory analyses equations double probe insertion electric currents modulated by radio frequency and an exact solution for thin-sheath approximation is derived. case ion curve strongly dependent on voltage also considered leads to a new method compensation derivation which, together experimental results, gives electron temperature. Measurements which support above are presented. temperature...
The H-mode pedestal characteristics on the mega ampère spherical tokamak (MAST) are measured in a variety of disconnected double null discharges and effect edge localized modes (ELMs) is presented. density width spatial co-ordinates similar both inboard outboard sides. Neutral penetration may be able to explain but it alone cannot temperature pedestal. data from MAST can used improve scalings by extending ranges collisionality, magnetic field, elongation aspect ratio studied other machines....
For a fusion power plant to be economically and technologically attractive, it should as compact possible capable of `steady state' operation. One approach is based upon the spherical tokamak (ST) concept. This configuration features many qualities conventional aspect ratio tokamak, such good confinement MHD stability, together with number highly promising for realization cost effective, steady state core. In particular, allows high β capability due I/B achievable at low A strong, natural...
H-mode plasmas have been achieved on the MAST spherical tokamak at input power considerably higher than predicted by conventional threshold scalings. Following L- H transition, a clear improvement in energy confinement is obtained, exceeding recent international scalings even densities approaching Greenwald density limit. Transition accompanied an order-of-magnitude increase edge-density gradient, marked decrease turbulence, efficient conversion of internal electron Bernstein waves into free...
Substantial advances have been made on the Mega Ampère Spherical Tokamak (MAST). The parameter range of MAST confinement database has extended and it now also includes pellet-fuelled discharges. Good pellet retention observed in H-mode discharges without triggering an ELM or H/L transition during peripheral ablation low speed pellets. Co-ordinated studies DIII-D demonstrate a strong link between aspect ratio beta scaling energy confinement, consistent with that obtained when data were merged...
Operating scenarios in the Mega-Ampère Spherical Tokamak (MAST) have been recently developed to access routinely H-mode plasmas over a wide range of plasma conditions. Gas refuelling at inboard mid-plane has proved invaluable facilitating L- transitions. Already, comprehensive behaviour observed providing similar and contrasting comparisons with conventional tokamaks. For example, similarities are found edge global evolutions, increases confinement ELM behaviour. In contrast, threshold...
Low aspect ratio plasmas in devices such as the mega ampere spherical tokamak (MAST) are characterized by strong toroidicity, shaping and self fields, low magnetic field, high beta, large plasma flow intrinsic E × B shear. These characteristics have important effects on behaviour, provide a stringent test of theories scaling laws offer new insight into underlying physical processes, often through amplification present conventional tokamaks (e.g. impact fuelling source geometry H-mode...
A comparison of the spatial and temporal evolution filamentary structures observed during type I ELMs is presented from a variety diagnostics machines. There evidence that these filaments can be detected inside LCFS prior to ELMs. The do not have circular cross section instead they are elongated in perpendicular (poloidal) direction this size appears increase linearly with minor radius machine. start off rotating toroidally/poloidally velocities close pedestal. This velocity then decreases...
Significant progress has been made on the Mega Ampere Spherical Tokamak (MAST) towards a fundamental understanding of transport, stability and edge physics addressing technological issues for future large devices. Collaborative studies L–H transition with NSTX ASDEX Upgrade confirm that operation in connected double-null configuration significantly reduces threshold power, Pthr. The MAST data provide support theory based finite β drift wave turbulence suppression by self-generated zonal...