A5065405104- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Complex Systems and Time Series Analysis
- Theoretical and Computational Physics
- Particle accelerators and beam dynamics
- Nuclear Materials and Properties
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Meteorological Phenomena and Simulations
- Thermography and Photoacoustic Techniques
- Ultrasonics and Acoustic Wave Propagation
- Fluid Dynamics and Turbulent Flows
- Ion-surface interactions and analysis
- Advanced Measurement and Detection Methods
- Engineering and Test Systems
- Advanced Fiber Optic Sensors
- Nuclear Engineering Thermal-Hydraulics
- Industrial Vision Systems and Defect Detection
- Laser-induced spectroscopy and plasma
- Physics of Superconductivity and Magnetism
- Risk Perception and Management
Culham Centre for Fusion Energy
1992-2024
Culham Science Centre
2003-2024
United Kingdom Atomic Energy Authority
2022
Hiden Analytical (United Kingdom)
2009
Joint European Torus
1995-2003
Oak Ridge National Laboratory
1998-2003
Royal Holloway University of London
1996
University of Warwick
1990
The laser generation of ultrasound in solids is reviewed with particular emphasis on the application this unique ultrasonic source. Three regimes for using lasers visible near infrared wavelength region exist: thermoelastic, plasma and constrained surface source regimes. mechanism each these given. Recent experimental investigations into laser-generated are also described, including a description different CO2 laser. Finally, many applications reviewed. These range from nondestructive...
The experimental characteristics of divertor detachment in the JET tokamak with Mark I pumped are presented for ohmic, L mode and ELMy H experiments main emphasis on discharges deuterium fuelling only. range over which is observed various regimes, as well influence configuration, direction toroidal field, target material active pumping detachment, will be described. characteristics, such existence a considerable electron pressure drop along field lines scrape-off layer (SOL), compatibility...
Analysis of the edge plasma fluctuation in several confinement devices reveals self-similar character fluctuations through presence long-range time correlations. These results show that tail autocorrelation function decays as a power law for lags longer than decorrelation and long times on order particle diffusion time. The algebraic decay correlations is consistent with transport characterized by self-organized criticality.
The rescaled range analysis techniques are used to investigate long-range dependence in plasma edge fluctuations [Mandelbrot and Wallis, Water Resources Res. 4, 909 (1969)]. This technology has been applied data from several confinement devices such as tokamaks, stellarators, reversed-field pinch. results reveal the self-similar character of electrostatic at with self-similarity parameters ranging 0.62 0.72. These show that tail autocorrelation function decays a power law for time lags...
In the Pre-Concept Design Phase of EU-DEMO, work package TFV (Tritium – Matter Injection Vacuum) has developed a tritium self-sufficient three-loop fuel cycle architecture. Driven by need to reduce inventory in systems an absolute minimum, this requires continual recirculation gases loops without storage, avoiding hold-ups each process stage giving preference continuous over batch technologies, and immediate use extracted from breeding blankets. order achieve goal, number novel concepts...
An overview of JET experimental results in DT plasmas directly relevant to ITER modes operation is presented. Experiments D:T mixtures varying from 100:0 10:90 and those carried out hydrogen show that the H mode threshold power has an approximately inverse isotope mass dependence. Matching some key dimensionless parameters values, similarity experiments with shape safety factor q global energy confinement time practically independent isotopic (~A0.03±0.08), where A atomic hydrogenic species....
Frequency spectra of fluctuations the ion saturation current, floating potential, and turbulent transport measured in plasma edge different fusion devices (tokamaks stellarators) have been compared. All show same behavior over whole frequency range investigated, which supports universality turbulence or transport. The results obtained are an indication edge-plasma evolving into a critical state, independent size characteristics device.
Results of experiments investigating the performance JET Mark IIA divertor are reported and compared with its I predecessor. The principal effect reducing width (increasing closure) was to increase pumping for both deuterium impurities while upstream neutral pressure. Neither orientation target relative plasma nor had a major influence on core in ELMy H modes. Changing triangularity thus edge magnetic shear modifies ELM frequency mode plasmas, thereby changing peak power loading. integrated...
In current large tokamaks, non-intrinsic seeded impurities have been used to produce divertor power loads which would be considered acceptable when extrapolated ITER. Many devices achieved the goals of high fractional radiated powers, small frequent ELMs and detachment are characteristic radiative H mode regimes. The influence geometry on these characteristics is described. It has a matter concern that Zeff associated with may exceed allowable in ITER also degradation energy confinement...
Retarding field analyzers (RFAs) are essentially the only practical tool with which to measure distribution of ion energies in boundary plasma magnetic fusion devices. The technique has long been attempted such facilities varying degrees success, but, by virtue delicate nature these material probes and hostile environment they inserted, its use limited smaller machines easier access more tolerable conditions. This article describes detail a new RFA probe head recently constructed tested on...
Self-ion irradiation of pure tungsten with 2 MeV W ions provides a way simulating microstructures generated by neutron in components fusion reactor. Transmission electron microscopy (TEM) has been used to characterize defects formed samples ion irradiation. It was found that irradiated 0.85 dpa at relatively low temperatures develops characteristic microstructure dominated dislocation loops and black dots. The density size distribution these were estimated. Some the exposed self-ion then...
To better understand long time transport dynamics, techniques to investigate long-range dependences in plasma fluctuations have been applied data from several confinement devices including tokamaks, stellarators, and reversed field pinch. The results reveal the self-similar character of edge fluctuations. This implies that tail autocorrelation function decays as a power law suggests there is superdiffusive component anomalous transport. Rescaled fluctuation turbulent flux spectra different...
A retarding field analyser (RFA) mounted on one of the JET reciprocating probe drives has been used to measure ion temperature in boundary plasma. This paper describes design RFA and special requirements for energy analysis. The first results are presented, together with simulations by DIVIMP code using measurements Langmuir probes at divertor plates as input "Onion-Skin" plasma model.
Dedicated experiments on JET clarified the effect of toroidal field reversal divertor asymmetries. In high recycling L-mode discharges had a significant impact density, temperature, radiated power, particle flux and emission distribution between strike zones. The in/out ratio was reduced following change from `normal' to `reversed' configuration, while asymmetry increased. This behaviour is consistent with previous observations suggests radial drift as possible candidate explain observed...
Frequency spectra of fluctuations for the ion saturation current, floating potential, and turbulent transport measured in plasma edge confinement experiments (tokamaks stellarators) have been analyzed to identify frequency ranges characterized by a power dependence. Three main regions can be identified. For intermediate region, decay is close 1/f, as expected self-organized criticality systems. This region particularly important role that it plays self-similarity fluxes. The effect rotation...
A new facility to study the interaction of hydrogen isotopes with nuclear fusion-relevant first wall materials, and their retention release, has been produced. The allows for implanting a range gases into samples, including tritium. An accurate isotope effects, such as isotopic exchange in damaged microstructure, previously difficult due background signal light hydrogen. This capability will allow virtually free measurements using tritium deuterium. design build this are described...
On the basis of experiments carried out in JET D:T mixtures varying from 100:0 to 5:95 and those hydrogen plasmas, isotopic mass dependence ELM parameters edge pedestal pressure NBI ICRF heated H mode plasmas is presented. The frequency found decrease with atomic number both ICRH discharges. However, case about 8-10 times higher than that NBI. Assuming ELMs occur at a critical gradient, limited by ballooning instability, scaling maximum most consistent assumption width transport barrier...
Experimental plasma-edge gradients in JET during the edge-localized-mode (ELM) free H-mode are examined for evidence of presence and location transport barrier region inside magnetic separatrix. High spatial resolution data electron density is available in- outside separatrix from an Li-beam diagnostic, temperature ECE while separatrix, a reciprocating probe provides scrape-off layer. Ion temperatures densities measured using edge charge-exchange diagnostic. A comparison observed widths this...
The EDGE2D code with drifts can reproduce the main trends of target asymmetries observed in field reversal experiments. It also reproduces qualitatively feature recent JET results obtained double-sided reciprocating Langmuir probes introduced near top torus: parallel plasma flow toroidal reversal. suggest that major contributor to is co-current momentum generated inside scrape-off layer (SOL) by jr × B forces due presence large up-down pressure asymmetries. Contrary previous expectations...