S. Menmuir
A5106481831- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Brake Systems and Friction Analysis
- Advanced Chemical Physics Studies
- Cold Fusion and Nuclear Reactions
- Nuclear Materials and Properties
- Electrostatic Discharge in Electronics
- Advanced Frequency and Time Standards
- Plasma and Flow Control in Aerodynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Robot Manipulation and Learning
- Fault Detection and Control Systems
- Electromagnetic Compatibility and Measurements
Culham Centre for Fusion Energy
2017-2024
United Kingdom Atomic Energy Authority
2018-2024
Culham Science Centre
2015-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2024
CEA Cadarache
2016-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2023
Royal Military Academy
2020
KTH Royal Institute of Technology
2005-2015
National Agency for New Technologies, Energy and Sustainable Economic Development
2009-2011
Abstract The quasi-continuous exhaust (QCE) regime is a that naturally type-I ELM-free. It combines the high density at plasma edge needed for power with normalised energy confinement typical H-mode operation. In QCE large-scale ELMs are avoided and high-frequent, low-amplitude filaments present leading to name-giving transport of particles energy.
This contribution reports first time was successfully achieved in JET metal wall. More so, it demonstrated recent deuterium-tritium...
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...
Abstract The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with ITER-like Be/W wall. development started pure Deuterium refinement of current, and toroidal magnetic field choices succeeded solving heat load challenges arising 37 MW injected power ITER like environment, keeping radiation edge core controlled, avoiding MHD instabilities reaching high neutron rates. have re-run Tritium...
This paper reports the progress made at JET-ILW on integrating requirements of reference ITER baseline scenario with normalized confinement factor 1, a pressure 1.8 together partially detached divertor whilst maintaining these conditions over many energy times. The 2.5 MA high triangularity ELMy H-modes are studied two different configurations D-gas injection and nitrogen seeding. power load reduction N seeding is reported. relationship between an increase in pedestal investigated....
This paper summarizes the physical principles behind novel three-ion scenarios using radio frequency waves in ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for and fast-ion generation multi-ion species plasmas. The theoretical section provides practical recipes selecting plasma composition realize scenarios, including two equivalent possibilities choice resonant absorbers that have been identified....
Abstract The work describes the pedestal structure, transport and stability in an effective mass ( A eff ) scan from pure deuterium to tritium plasmas using a type I ELMy H-mode dataset which key parameters that affect behaviour (normalized pressure, ratio of separatrix density density, ion Larmor radius, collisionality rotation) are kept as constant possible. Experimental results show significant increase at top with increasing , modest reduction temperature pressure. variations heights...
Abstract As part the DTE2 campaign in JET tokamak, we conducted a parameter scan T and D-T complementing existing pulses H D. For different main ion masses, type-I ELMy H-modes at fixed plasma current magnetic field can have pedestal pressure varying by factor of 4 total changing from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>β</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">N</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo>...
Abstract In the paper we present an overview of interpretive modelling a database JET-ILW 2021 D-T discharges using TRANSP code. The main aim is to assess our capability computationally reproducing fusion performance various plasma scenarios different external heating and mixtures, understand driving mechanisms. We find that simulations confirm general power-law relationship between increasing power output, which supported by absolutely calibrated neutron yield measurements. A comparison...
Abstract This paper presents a study on the dependence of ion temperature stiffness plasma main isotope mass in JET ITER-like wall and C discharges. To this aim, database H, D T shots is analyzed, including new dedicated shots, comparing experiments with lower higher power injected by NBI system. In order to characterize turbulence mass, three these discharges (two one D) same external heating scheme are studied detail interpreted gyrokinetic linear nonlinear simulations. The analysis...
The fusion-born alpha particle heating in magnetically confined fusion machines is a high priority subject for studies. self-heating of thermonuclear plasma by particles was observed recent deuterium-tritium (D-T) experiments on the joint European torus. This observation possible conducting so-called "afterglow" where transient yield achieved with neutral beam injection as only external source, and then termination at peak performance. allowed first direct evidence electron plasmas alphas to...
Abstract The reference ion cyclotron resonance frequency (ICRF) heating schemes for ITER deuterium–tritium (D-T) plasmas at the full magnetic field of 5.3 T are second harmonic and 3 He minority heating. wave-particle location these coincide central a wave 53 MHz T. Experiments have been carried out in major D-T campaign (DTE2) JET, its prior D campaigns, to integrate ICRF scenarios JET high-performance compare their performance with commonly used hydrogen (H) In 50:50 D:T plasmas, up 35% 5%...
Abstract The dimensionless isotope mass scaling experiment between pure Deuterium and Tritium plasmas with matched <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> , <mml:mi>ν</mml:mi> β n q <mml:msub> <mml:mi>T</mml:mi> <mml:mi>e</mml:mi> </mml:msub> <mml:mrow> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi>i</mml:mi> has been achieved in JET L-mode dominant electron heating (NBI+ohmic) conditions....
Abstract This paper reports the first experiment carried out in deuterium–tritium addressing integration of a radiative divertor for heat-load control with good confinement. Neon seeding was time D–T plasma as part second campaign JET its Be/W wall environment. The technical difficulties linked to re-ionisation heat load are reported T and D–T. compares impact neon on plasmas their D counterpart detachment, localisation radiation, scrape-off profiles, pedestal structure, edge localised modes global
Abstract The fusion reaction between deuterium and tritium, D ( T,n ) 4 He is the main source of energy in future thermonuclear reactors. Alpha-particles -ions) born with an average 3.5 MeV transferring to thermal plasma during their slowing down, should provide self-sustained D–T burn. adequate confinement α -particles essential efficient heating bulk steady burning a reactor plasma. That why fusion-born -particle studies have been priority task second experiments (DTE2) on Joint European...
Abstract JET returned to deuterium-tritium operations in 2023 (DTE3 campaign), approximately two years after DTE2. DTE3 was designed as an extension of JET's 2022-2023 deuterium campaigns, which focused on developing scenarios for ITER and DEMO, integrating in-depth physics understanding control schemes. These were evaluated with mixed D-T fuel, using the only remaining tritium-capable tokamak until its closure 2023. A core-edge-SOL integrated H-mode scenario developed tested D-T, showing...
In DT plasmas, toroidal Alfvén eigenmodes (TAEs) can be made unstable by the alpha particles resulting from fusion reactions, and may induce a significant redistribution of fast ions. Recent experiments have been conducted in JET deuterium plasmas order to prepare scenarios aimed at observing alpha-driven TAEs future campaign. Discharges low density, large core temperatures associated with presence internal transport barriers characterised good energetic ion confinement performed. ICRH has...
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...
With the exploration of MA plasma current regime in up to 0.5 s long discharges, RFX-mod has opened new and very promising perspectives for reversed field pinch (RFP) magnetic configuration, made significant progress understanding improving confinement controlling stability. A big leap with respect previous knowledge expectations on RFP physics performance been by since last 2006 IAEA Fusion Energy Conference. self-organized helical equilibrium experimentally achieved (the Single Helical...
Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement respect to the carbon (JET-C). The main differences observed were (1) strong accumulation of W in plasma core (2) need mitigate divertor target temperature avoid sputtering by Be other low Z impurities (3) decrease confinement. A major difference is pedestal pressure, namely reduction which, due profile stiffness also reduced leading degradation global This effect more pronounced β N...
Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of ITER-like wall. The line intensities are weaker and contaminated by many nuisance lines. We have therefore upgraded instrumentation to improve throughput allow simultaneous measurement impurity fuel-ion charge exchange splitting light between two pairs imaging spectrometers using dichroic beam splitters. Imaging instruments us stack 11 × 1 mm diameter fibres entrance slits without cross talk. CCD...
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)...
In present and future magnetic confined fusion devices with metallic plasma-facing components (PFCs) such as JET-ILW ITER, the calculation of plasma composition must account for multiple impurities a wide range mass charge, resolve their poloidal asymmetries different central peakings various elements. Single measurements radiation effective charge are not enough to characterize this complex system self-consistent analysis data from diagnostics is required. This contribution describes method...