A5015739535- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Fusion materials and technologies
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- Atomic and Molecular Physics
- Nuclear Materials and Properties
- Particle Accelerators and Free-Electron Lasers
- Mass Spectrometry Techniques and Applications
- Laser-Plasma Interactions and Diagnostics
- Metal and Thin Film Mechanics
- Gyrotron and Vacuum Electronics Research
- Ion-surface interactions and analysis
- Superconductivity in MgB2 and Alloys
- Dust and Plasma Wave Phenomena
- Muon and positron interactions and applications
- Plasma Applications and Diagnostics
- High Temperature Alloys and Creep
- Laser-induced spectroscopy and plasma
- Microstructure and Mechanical Properties of Steels
- Electrohydrodynamics and Fluid Dynamics
- Ionosphere and magnetosphere dynamics
Culham Centre for Fusion Energy
2010-2023
Culham Science Centre
2013-2023
United Kingdom Atomic Energy Authority
2003-2022
Ricardo AEA (United Kingdom)
1990-2018
London Metropolitan University
1987
Real-time simultaneous control of several radially distributed magnetic and kinetic plasma parameters is being investigated on JET, in view developing integrated advanced tokamak scenarios. This paper describes the new model-based profile controller which has been implemented during 2006–2007 experimental campaigns. The aims to use combination heating current drive (H&CD) systems—and optionally poloidal field (PF) system—in an optimal way regulate evolution parameter profiles such as...
Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or soldered provide the solution for demountable magnets, a critical component building block both will be many, smaller-scale that enable supercurrent leave layer, cross tape and pass into solder lies between conductor eventually provides one of surfaces. This paper considers electrical thermal properties this essential part high temperature (HTS)...
A one-dimensional analytical model of the sheath in a negative ion source, such as those proposed for heating and diagnostic beams on present future fusion devices, has been developed. The model, which is collisionless, describes transport surface produced ions from cathode, across to plasma containing electrons, positive ions. It accounts situation where emitted flux greater than space charge limit, electric field at cathode negative, virtual formed. shown that, presence there maximum...
Several collisional–radiative (CR) models (Anderson et al 2000 Plasma Phys. Control. Fusion 42 781–806, Hutchinson 2002 44 71–82, Marchuk 2008 Rev. Sci. Instrum. 79 10F532) have been developed to calculate the attenuation and population of excited states hydrogen or deuterium beams injected into tokamak plasmas. The datasets generated by these CR are needed for modelling beam ion deposition (excited) densities in current experiments, reliability data will be crucial obtain helium ash on ITER...
Results are presented from the JET Trace Tritium Experimental (TTE) campaign using minority tritium (T) plasmas (n(T)/n(D) 2 MA) and monotonic q-profiles. In CH discharges gamma-ray emission decay times much lower than classical (tau(Ts) + tau(alpha s)), indicating alpha confinement degradation, due to orbit losses particle drift predicted by a 3-D Fokker-Planck numerical code modelled TRANSP.
Trace tritium experiments (TTE) on JET were analysed using Monte Carlo modelling of the neutron emission resulting from neutral beam injection (NBI) short (~300 ms) (T) blips into reversed shear, hybrid ELMy H-mode and L-mode deuterium plasmas for a wide range plasma parameters. The calculated fluxes deuterium–tritium (DT) reactions could only be made consistent with all by applying an artificial reduction T power in between 20% 40%. A similar discrepancy has previously been observed both...
In 2007 the IPP RF driven negative hydrogen ion source was chosen by ITER board as new reference for neutral beam system. order to support design of Neutral Beam Test Facility in Padua and its commissioning operating phases, is presently constructing a test facility ELISE (Extraction from Large Ion Source Experiment) large‐scale extraction half‐size source. Plasma operation up one hour foreseen; but due limits HV system, pulsed only possible. The system designed acceleration ions 60 kV....
The improvement of the efficiency neutral beam systems to be compatible with economic requirements fusion power plants is a key theme in European research programme. A novel plasma neutralizer, which negative ion itself source plasma, described. Its success depends on confinement free electrons generated by stripping from and their generation additional plasma. device requires no contrast photoneutralizer, presently main interest. Although not as high photoneutralizer it essentially low...
The major aspects linked to the use of JET auxiliary heating systems: NBI, ICRF and LHCD, in new ITER-like wall (JET-ILW) are presented. We show that although there were issues related operation each system, efficient safe plasma was obtained with room for higher power. For NBI up 25.7MW safely injected; had be tackled mainly beam shine-through re-ionisation before its entrance into plasma. 5MW coupled L-mode 4MW H-mode; main areas concern RF-sheaths heat loads impurities production. LH, 2.5...
The potential for reducing the Cost of Electricity (CoE) by using High Temperature Superconductors (HTS) in Toroidal Field (TF) coils a fusion tokamak power plant has been investigated new HTS module PROCESS systems code. We report CoE and design tokamaks that have optimised minimising major radius plasma. Potential future improvements both superconducting properties structural materials TF operating at 4.8 K 30 are considered. Increasing critical current density factor 10 (with commensurate...
All large superconducting applications require electrical connections between superconductors or and other metallic parts of the systems. Such are essential components for these usually made by melting solder (or soft soldering). In general, point, resistivity, mechanical wetting properties, toxicity all important criteria when choosing best a specific application. If itself is under operating conditions application, then there also possibility extremely low resistance joints. this work, we...
Abstract A fusion power plant can only exist with physics and technology acting in synchrony, over space (angstroms to tens of metres) time (femtoseconds decades). Recent experience the European DEMO programme has shown how important it is start integration early, yet go deep enough uncover impact, favourable unfavourable, detailed physical technological characteristics. There are some initially surprising interactions, for example, density links properties materials components approaches...
The first measurement of an elevated temperature the target gas in a neutralizer cell, resulting from interaction with beam, is reported. Effects unique to beam–plasma system are considered particular reference relevance experimental spectroscopic analysis technique. found reach temperatures up 900 K for operation multi-megawatt positive ion beams.
LBNL designed and built the Frontend for Spallation Neutron Source, including its H− source Low‐Energy Beam Transport (LEBT). This paper discusses performance of LEBT during commissioning accelerator, as well their while ramping up SNS beam power to 540 kW. Detailed discussions major shortcomings mitigations are presented illustrate effort needed take even a well‐designed R&D ion into operation. With these modifications, at 4% duty factor meets essential requirements that were set beginning project.
An exploratory study of negative ion beam photo‐neutralization for future fusion reactors is explained. A refolded Fabry‐Perot cavity system proposed, with which a 60% neutralisation efficiency could be reached low electric power consumption. The would make use sophisticated optical‐cavity locking systems, have been developed recently gravitational‐wave optical detection. ITER Neutral Injector taken as an example.
There are several programmes within the fusion community that engaged in design of devices to follow International Thermonuclear Experimental Reactor (ITER), referred as ‘demonstrators’. These have identified many issues over past decade, and research now concentrates on optimizing combination systems against a set Key Performance Indicators (KPI) which may vary between programmes. While return investment experience from ITER is seen an important factor this there significant differences...
There is an increasing need to model plasma interaction with complex engineered surfaces, notably verify that power deposition rates are acceptable. The SMARDDA algorithm has been developed meet this requirement, particular reference the neutral beam ducts feed into vacuum vessels of tokamaks. Application limiters and divertors made in a companion paper. described detail, highlighting key novel features, illustrative duct calculations presented.
Indirect heating of the neutralizer gas by beam has been shown to be responsible for reduced neutralization efficiency observed in positive ion neutral systems. The translational temperature can predicted from plasma density and electron and, general, a higher implies lower target. A simple one-dimensional model, originally developed JET injection system, adapted ITER relevant negative results imply that diagnostic beams is unlikely severe hence target might expected close design value.
A Test Facility is planned to be built in Padova assemble and test the Neutral Beam Injector for ITER. In same Ion Source will tested a dedicated facility operate parallel main 1 MV facility. Purpose of full size optimize performance by maximizing extracted negative ion current density its spatial uniformity minimizing ratio co‐extracted electrons. this contribution design extractor accelerator grids 100 kV, 60 system presented. The trajectories ions, calculated with SLACCAD code [1], have...