J. Flanagan
A5019033204- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Photonic Crystal and Fiber Optics
- Advanced Fiber Laser Technologies
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Advanced Fiber Optic Sensors
- Optical Network Technologies
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Laser-induced spectroscopy and plasma
- Optical Coherence Tomography Applications
- Particle physics theoretical and experimental studies
- Solar and Space Plasma Dynamics
- Nuclear Engineering Thermal-Hydraulics
- Advanced Optical Sensing Technologies
- Laser Material Processing Techniques
- Water Quality Monitoring and Analysis
- Odor and Emission Control Technologies
- Quantum Chromodynamics and Particle Interactions
Culham Centre for Fusion Energy
2011-2024
Culham Science Centre
2014-2024
United Kingdom Atomic Energy Authority
2009-2024
Royal Military Academy
2020
University of Southampton
2006-2017
University of York
2013
University of Lisbon
2013
Forschungszentrum Jülich
2013
Fusion for Energy
2013
École Polytechnique Fédérale de Lausanne
2012
In this paper, the properties of nonsilica glasses and related technology for microstructured fiber fabrication are reviewed. Numerical simulation results shown using fibers mid-infrared (mid-IR) supercontinuum generation when seeding with near-IR, 200-fs pump pulses. particular, bismuth glass small-core that have two zero-dispersion wavelengths (ZDWs) investigated, efficient mid-IR is enabled by phase-matching a 2.0-mum seed across upper ZDW into 3-4.5 mum wavelength range. Fiber lengths...
We report the fabrication of a large mode area tellurite holey fiber from an extruded preform, with 3000μm 2 .Robust single-mode guidance at 1.55μm was confirmed by both optical measurement and numerical simulation.The propagation loss measured as 2.9dB/m 1.55μm.A broad flat supercontinuum 0.9 to 2.5μm 6mW output obtained 9cm length this fiber.
This paper reports the impact on confinement and power load of high-shape 2.5 MA ELMy H-mode scenario at JET a change from all carbon plasma-facing components to an metal wall. In preparation this change, systematic studies reduction as result fuelling in combination with nitrogen seeding were carried out JET-C are compared their counterpart metallic An unexpected significant is reported decrease pedestal but partially recovered injection nitrogen.
The dependence of plasma transport and confinement on the main hydrogenic ion isotope mass is fundamental importance for understanding turbulent and, therefore, accurate extrapolations from present tokamak experiments, which typically use a single hydrogen isotope, to burning plasmas such as ITER, will operate in deuterium–tritium mixtures. Knowledge properties edge barrier formation species critical view initial, low-activation phase ITER operations or helium its implications subsequent...
The impact of carbon and beryllium/tungsten as plasma-facing components on plasma radiation, divertor power particle fluxes, neutral conditions in the divertors has been assessed JET both experimentally by edge fluid code simulations for plasmas low-confinement mode. In high-recycling studies show a 30% reduction total radiation scrape-off (SOL) layer when replacing (JET-C) with beryllium main chamber tungsten (JET-ILW). Correspondingly, at low-field side (LFS) plate two-fold increase...
A comparison of the L–H power threshold (Pthr) in JET with all carbon, JET-C, and beryllium/tungsten wall (the ITER-like choice), JET-ILW, has been carried out experiments slow input ramps matched plasma shapes, divertor configuration IP/BT pairs. The low density dependence threshold, namely an increase below a minimum ne,min, which was first observed MkII-GB C subsequently not current MkII-HD geometry, is again JET-ILW. At densities above Pthr reduced by ∼30%, ∼40% when radiation from bulk...
The instrument function of the high resolution Thomson scattering (HRTS) diagnostic in Joint European Torus (JET) has been calculated for use improved pedestal profile analysis. full width at half maximum (FWHM) spatial response is (22 ± 1) mm original HRTS system configuration and depends on particular magnetic topology JET plasmas. An improvement to optical design laser input presented. smearing across flux surfaces reduced this design. new implemented (from JPN 78742, July 2009)...
In both JET and ASDEX Upgrade (AUG) the plasma energy confinement has been affected by presence of a metal wall requirement increased gas-fuelling to avoid tungsten pollution plasma.In with beryllium/tungsten high triangularity baseline H-mode scenario (i.e.similar ITER reference scenario) strongest benefit shaping give good normalised H 98 ~1 at Greenwald density fraction f GW ~0.8 disappeared.In AUG full could be achieved in plasmas, albeit elevated pressure β N >2.The lost respect carbon...
Disruptions are a critical issue for ITER because of the high thermal and magnetic energies that released on short timescales, which results in extreme forces heat loads. The choice material plasma-facing components (PFCs) can have significant impact loads arise during disruption. With ITER-like wall (ILW) JET made beryllium main chamber tungsten divertor, finding is low fraction radiation. This has dropped significantly with ILW from 50–100% total energy being dissipated disruptions CFC...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation M. N. A. Beurskens, T. H. Osborne, P. Schneider, E. Wolfrum, L. Frassinetti, R. Groebner, Lomas, I. Nunes, S. Saarelma, Scannell, B. Snyder, D. Zarzoso, Balboa, Bray, Brix, J. Flanagan, C. Giroud, Giovannozzi, Kempenaars, Loarte, de la Luna, G. Maddison, F. Maggi, McDonald, Pasqualotto, Saibene, Sartori, Emilia...
The new full-metal ITER-like wall (ILW) at JET was found to have a profound impact on the physics of disruptions. main difference is significantly lower fraction (by up factor 5) energy radiated during disruption process, yielding higher plasma temperatures after thermal quench and thus longer current times. Thus, larger total conducted resulting in heat loads. Active mitigation by means massive gas injection became necessity avoid beryllium melting already moderate levels magnetic (i.e....
In the recent JET experimental campaigns with new ITER-like wall (JET-ILW), major progress has been achieved in characterization and operation of H-mode regime metallic environments: (i) plasma breakdown at first attempt X-point L-mode recovered a few days operation; (ii) stationary stable type-I ELMy H-modes βN ∼ 1.4 have low high triangularity shape plasmas are showing that their operational domain H = 1 is significantly reduced JET-ILW mainly because need to inject large amount gas (above...
Type I ELMy H-mode operation in JET with the ITER-like Be/W wall (JET-ILW) generally occurs at lower pedestal pressures compared to those full carbon (JET-C). The density is similar but temperature where type ELMs occur reduced and below so-called critical I–type III transition reported JET-C experiments. Furthermore, confinement factor H98(y,2) baseline plasmas JET-ILW low power fractions Ploss/Pthr,08 < 2 (where Ploss (Pin − dW/dt), Pthr,08 L–H threshold from Martin et al 2008 (J. Phys....
Abstract We present an overview of results from a series L–H transition experiments undertaken at JET since the installation ITER-like-wall (JET-ILW), with beryllium wall tiles and tungsten divertor. Tritium, helium deuterium plasmas have been investigated. Initial in tritium show ohmic transitions low density power threshold for ( P LH ) is lower than ones densities, while we still lack contrasted data to provide scaling high densities. In there notable shift which minimum <?CDATA...
We present an improved measurement of CP-violation parameters in B0-->phiK(0)(S), K(+)K(-)K(0)(S), and eta(')K(0)(S) decays based on a 140 fb(-1) data sample collected at the Upsilon(4S) resonance with Belle detector KEKB energy-asymmetric e(+)e(-) collider. One neutral B meson is fully reconstructed one specified decay channels, flavor accompanying identified from its products. for each three modes are obtained asymmetries distributions proper-time intervals between two decays. find that...
We report the observation of flavor-changing neutral current decay B-->K(*)l(+)l(-) and an im-proved measurement B-->Kl(+)l(-), where l represents electron or a muon, with data sample 140 fb(-1) accumulated at Upsilon(4S) resonance Belle detector KEKB. The results for branching fractions are B(B-->K(*)l(+)l(-))=(11.5(+2.6)(-2.4)+/-0.8+/-0.2)x10(-7) B(B-->Kl(+)l(-))=(4.8(+1.0)(-0.9)+/-0.3+/-0.1)x10(-7), first error is statistical, second systematic third from model dependence.
We present the pedestal structure, as determined from high-resolution Thomson scattering measurements, for a database of low and high triangularity (δ ≈ 0.22–0.39) 2.5 MA, type I ELMy H-mode JET plasmas after installation new ITER-like wall (JET-ILW). The explores effect increasing deuterium fuelling nitrogen seeding with view to explain observed changes in performance (edge global). JET-ILW show no significant change structure gas dosing. These results are good agreement EPED1 predictions....
NBI-heated L-mode plasmas have been obtained in JET with the Be/W ITER-like wall (JET-ILW) H and D, matched profiles of dimensionless plasma parameters, ρ * , ν β q core confinement region same T i /T e Z eff .The achieved isotope identity indicates that scale invariance principle is satisfied these plasmas, where dominant instabilities are Ion Temperature Gradient (ITG) modes.The thermal energy time, Ω τ E,th scaled heat diffusivity, A χ /B identical D within error bars, indicating lack...
Abstract A reduction of the pedestal pressure with increasing separatrix density over ( n e sep / ped ) has been observed in JET. The physics behind this correlation is investigated. due to two distinct mechanisms. increase till ≈0.4 shifts radially outwards, decreasing peeling-balloning stability and reducing height. effect position saturates above ≈ 0.4. For higher values, ascribed increased turbulent transport and, likely, resistive MHD effects. reduces ∇ /n , η transport. This gradient...
The dependence of the H-mode edge transport barrier width on normalized ion gyroradius (ρ * = ρ/a) in discharges with type I ELMs was examined experiments combining data for JET and DIII-D tokamaks.The plasma configuration as well local pressure (β), collisionality (ν ), Mach number ratio electron temperature at pedestal top were kept constant, while ρ varied by a factor four.The steep gradient region (T e ) density (n pedestals
Abstract Experiments on JET, with both the previous carbon wall (JET-C) and new Be/W (JET-ILW), have demonstrated efficacy of using a fast vertical plasma motion (known as kicks in JET) for active ELM control. In this paper we report series experiments that been recently conducted JET-ILW goal further improving physics understanding processes governing triggering ELMs via kicks. This is necessary step to confidently extrapolate control method ITER. shown can be reliably triggered provided...
The EDGE2D-EIRENE code is applied for simulation of divertor detachment during matched density ramp experiments in high triangularity, L-mode plasmas both JET-Carbon (JET-C) and JET-ITER-Like Wall (JET-ILW). runs without drifts includes either C or Be as impurity, but not W, assuming that the W targets have been coated with via main chamber migration. simulations reproduce reasonably well observed particle flux raised JET-C JET-ILW can better match experimental in-out target power asymmetry...
The dynamics and stability of divertor detachment in N 2 seeded, type-I, ELMy H-mode plasmas with dominant NBI heating the JET ITER-like wall device is studied by means an integrated analysis diagnostic data from several systems, classifying relative to ELM times.It thereby possible study response evolution control parameters (SOL input power, upstream density impurity fraction) prevailing during inter-ELM periods effect ELMs on detached divertor.A relatively comprehensive overview achieved,...
The pedestal structure of type I ELMy H-modes has been analysed for JET-ILW.The electron pressure width is independent ρ* and increases proportionally to √β pol,PED .Additional broadening the observed, at constant β , with increasing ν* and/or neutral gas injection contribution atomic physics effects in setting cannot as yet be ruled out.Neutral penetration alone does not determine shape edge density profile ratio temperature scale lengths transport barrier region, η e order 1.5-2.The...
Abstract A dimensionless collisionality scan in low-triangularity plasmas the Joint European Torus with ITER-like wall (JET-ILW) has been performed. The increase of normalized energy confinement (defined as ratio between thermal and Bohm time) decreasing is observed. Moreover, at low collisionality, a factor H 98 , comparable to JET-C, achieved. At high related degraded pedestal stability reduction density-profile peaking. due both an core regions. improvement stability. driven by (i)...