R.B. Morales
A5019246449- Magnetic confinement fusion research
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- High-Energy Particle Collisions Research
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Geophysical Methods and Applications
- Gyrotron and Vacuum Electronics Research
- Analytical Chemistry and Sensors
- Advanced X-ray and CT Imaging
- Advanced Measurement and Metrology Techniques
- Nuclear Materials and Properties
- Calibration and Measurement Techniques
- Seismic Imaging and Inversion Techniques
- Nuclear Engineering Thermal-Hydraulics
- Seismic Waves and Analysis
United Kingdom Atomic Energy Authority
2022-2024
Culham Centre for Fusion Energy
2020-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2024
CEA Cadarache
2024
Culham Science Centre
2020-2023
Institut Jean Lamour
2017-2020
Université de Lorraine
2017
Centre National de la Recherche Scientifique
2017
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...
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 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...
Abstract The recent deuterium–tritium campaign in JET-ILW (DTE2) has provided a unique opportunity to study the isotope dependence of L-H power threshold an ITER-like wall environment (Be and W divertor). Here we present results from dedicated transition experiments at JET-ILW, documenting tritium plasmas, comparing them with matching deuterium hydrogen datasets. From earlier it is known that as plasma isotopic composition changes deuterium, through varying deuterium/hydrogen concentrations,...
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 This study investigates the dependence of radial electric field (Er) on line-averaged density in JET L-mode plasmas, utilizing Doppler backscattering measurements. Density ramp discharges up to limit are analyzed investigate physical processes that determine edge Er profile. At low densities, profile at midplane exhibits a pronounced peak near scrape-off layer (SOL) and shallow well inside separatrix. As increases, SOL diminishes quickly deepens until Greenwald fraction fGW ≈ 0.8,...
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...
Abstract JET-ILW type I ELMy H-modes at 2.5 MA/2.8 T with constant NBI heating (23 MW) and gas fuelling rate were performed, utilising edge localised mode (ELM) pacing by vertical kicks plasma shaping (triangularity, δ ) as tools to disentangle the effects of ELMs, inter-ELM transport stability on pedestal particle balance. In agreement previous studies, confinement improves increasing , mostly due a significant increase in density while ELM frequency ( <?CDATA $f_{\mathrm{ELM}}$?> <mml:math...
JET’s frequency-modulated continuous wave (FMCW) reflectometers have been operating well with the current design since 2005, and density profiles automatically calculated intershot then. However, had long suffered from several shortcomings: poor agreement other diagnostics, sometimes inappropriately moving radially by centimeters, elevated levels of radial jitter, persistent wriggles (strong unphysical oscillations). In this research, techniques are applied to reflectometry data analysis,...
Abstract Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under auspices of a single Task Force called ‘Tokamak Exploitation’. The goal to benefit from complementary capabilities each machine in coordinated way and help developing scientific output scalable future largre machines. programme this ensures that ASDEX Upgrade, MAST-U, TCV, WEST JET (since 2022) work together achieve objectives Missions 1 2 Roadmap: i) demonstrate plasma scenarios...
Abstract JET, the world’s largest operating tokamak with unique Be/W wall and tritium handling capability, completed a Deuterium-Tritium (D-T) campaign in 2021 (Maggi et al 29th Fusion Energy Conf. ) following decade of preparatory experiments, dedicated enhancements, technical rehearsals training (Horton 2016 Eng. Des. 109–111 925). Operation raises significant technical, safety scientific challenges not encountered standard protium or deuterium operation. This contribution describes...
Perpendicular velocity, v⊥, measurements have been obtained in JET experiments designed to investigate the underlying mechanisms influencing L–H power threshold. transitions were induced by using both NBI and ICRH deuterium helium plasmas. The v⊥ profile low density branch of transition has a modest or even no well marked peak near separatrix heated discharges for D He plasmas, with sharper SOL As line-averaged increases, decreases, agreement modifications electron temperature at divertor...
Abstract The role of the divertor configuration and plasma physics on L–H transition is poorly understood, leading to large uncertainties in predicting power threshold future devices. This contribution reports edge perpendicular flow measurements by Doppler backscattering JET experiments with outer strike-point at different positions: horizontal target (HT), vertical (VT), corner (between HT VTs). was found be significantly affected changes region inside separatrix. Our results do not show...
Abstract Strike-point sweeping, a technique often used to spread heat loads on divertor targets, was employed in JET experiments for the first time generate an edge-localized modulated particle source investigating plasma fuelling and transport edge region. This approach motivated by possibility of achieving higher modulation frequencies than those available from traditional gas puff at JET. Higher would enable collection more information electron density response source. Various sweeping...
Abstract A baseline scenario of deuterium–tritium (D–T) plasma with peripheral high-field-side fuelling pellets has been produced in JET order to mimic the situation ITER. The isotope mix ratio is controlled target value 50%–50% by a combination tritium gas puffing and deuterium pellet injection. Multiple factors controlling efficiency individual are analysed, following findings: (1) prompt particle losses due pellet-triggered edge-localised modes (ELMs) detected, (2) plasmoid drift velocity...
The reconstruction method published by Bottollier-Curtet and Ichtchenko in 1987 has been the standard of density profile for X-mode reflectometry ever since, with only minor revision. Envisaging improved accuracy stability method, functions more complex than linear are evaluated here to describe refractive index shape each integration step. obtained when using parabolic fixed or adaptative fractional power compared previous tested against spurious events phase noise. developed relation from...
Abstract Density peaking has been studied between an ICRH and NBI identity plasma in JET. The comparison shows that 8 MW of heating/fueling increases the density by a factor two, being R / L n = 0.45 for pulse 0.93 one averaged radially over ρ tor 0.4, 0.8. dimensionless profiles q , * υ β T i e ≈ 1 were matched within 5% difference except central part ( < 0.3). curvature pinch (same -profile) thermo-pinch ) discharges is virtually zero. Both gyro-kinetic simulations integrated modelling...
At the JET tokamak, three electron cyclotron emission (ECE) diagnostics (two Martin-Puplett interferometers and a heterodyne radiometer) reflectometer form basic microwave diagnostic system.The standard analysis approaches deduce density temperature profiles independently of each measurement.Via Bayesian framework Minerva, system is modelled, are inferred jointly for an Ohmic plasma.Furthermore, profile length-scales different plasma domains, magnetic field correction, distinct reflection...
All density profile reconstruction techniques for both O-mode and X-mode are based on the assumption that cut-off frequency is monotonic.However, experimentally, there many perturbations to plasma generate hollow areas in profile.They cause a significant immediate error not rapidly damped.It demonstrated even though no reflections occur inside region, higher probing frequencies propagate through this area carry information about it can be used estimate its properties.In addition, algorithm...
Abstract The publication provide further insights into the dynamics of JET runaway electron (RE) beams mitigated by D2-rich shattered pellet injection (SPI) (Reux et al 2022 Plasma Phys. Control. Fusion 64 034002). Multi-diagnostic analyses show that mechanisms causing continuous RE losses and energy transfer from hot electrons to cold background plasma can act before SPI. After SPI, measurements are compatible with a reduction maximum pitch angle distribution while population supra-thermal...
Abstract Recent JET D–T campaigns opened the possibility of unique isotope studies to investigate L–H transition physics in view reactor plasmas and study origin observed power threshold minimum. In present paper, we characterise transitions low high-density branches NBI-heated plasmas. As discussed has been hypothesised be determined by transport losses plasma ions, i.e. so-called ion heat flux ( Q i ). We first balance analysis evaluate at transition. Due experimental setting being similar...