D. Van Eester
A5042858797- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- High-Energy Particle Collisions Research
- Dust and Plasma Wave Phenomena
- Atomic and Molecular Physics
- Gyrotron and Vacuum Electronics Research
- Electrostatic Discharge in Electronics
- Antenna Design and Analysis
- Computational Fluid Dynamics and Aerodynamics
- Quantum, superfluid, helium dynamics
- Vacuum and Plasma Arcs
- Spacecraft and Cryogenic Technologies
- Ion-surface interactions and analysis
- Advanced Data Storage Technologies
- Numerical methods for differential equations
- High voltage insulation and dielectric phenomena
- High-pressure geophysics and materials
Royal Military Academy
2012-2024
European Steel Association
2017-2024
Laboratoire de Physique des Plasmas
1989-2024
Culham Science Centre
2009-2023
Max Planck Institute for Plasma Physics
2015-2023
Culham Centre for Fusion Energy
2016-2023
United Kingdom Atomic Energy Authority
2023
National Agency for New Technologies, Energy and Sustainable Economic Development
2022
University of Padua
2022
European Commission
2021
Experiments were carried out in the JET tokamak to determine critical ion temperature inverse gradient length (R/LTi=R|nablaTi|/Ti) for onset of modes and stiffness Ti profiles with respect deviations from value. Threshold have been compared linear nonlinear predictions gyrokinetic code GS2. Plasmas higher values toroidal rotation show a significant increase R/LTi, which is found be mainly due decrease level. This finding has implications on extrapolation future machines present day results...
New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [Phys. Rev. Lett. 102, 175002 (2009)] results from combined effect high rotational shear and low magnetic shear. The observations have important implications for understanding improved confinement advanced tokamak scenarios. Simulations using quasilinear fluid gyrofluid models show features mitigation, while nonlinear gyrokinetic simulations do not....
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 European DEMO is a pulsed device with pulse length of 2 hours. functions devoted to the heating and current drive system are: plasma breakdown, ramp-up flat-top where fusion reactions occur, control during phase, finally ramp-down. EU-DEMO project was in Pre-Concept Design Phase 2014-2020, meaning that some cases, design values precise requirements from physics point view were not yet frozen. A total 130 MW considered for all phases plasma: flat top, 30 required neoclassical tearing...
Abstract In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and between thermal ions fast particles generated by neutral beam injection (NBI) heating or accelerated electromagnetic wave in ion cyclotron range of frequencies (ICRFs). To complement experiments with 50/50 D/T mixtures maximizing reactivity, a scenario dominant non-thermal reactivity has been developed successfully demonstrated during second campaign DTE2, as it was predicted to...
Abstract Ion cyclotron resonance frequency (ICRF) heating has been an essential component in the development of high power H-mode scenarios Jet European Torus ITER-like wall (JET-ILW). The ICRF performance was improved by enhancing antenna-plasma coupling with dedicated main chamber gas injection, including preliminary minimization RF-induced plasma-wall interactions, while RF where optimized for core impurity screening terms ion position and minority hydrogen concentration. impact on...
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 In this work the onset of tearing modes in termination phase plasma pulses on JET is investigated. It shown that broadening or shrinking current density profile, as a consequence core hollowing an edge cooling electron temperature strongly increases probability destabilizing 2/1 mode also absence external trigger (e.g. sawtooth crash). Two parameters are defined to highlight changes shape profile can lead MHD instabilities and empirical stability diagram introduced into space two...
New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such are achieved by means of optimized particle fueling conditions input power, current, magnetic field, which lead to a self-organized state strong increase rotation ion temperature decrease edge density. An interplay between plasma regions leads reduced turbulence levels outward...
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...
The spectral broadening of characteristic γ-ray emission peaks from the reaction (12)C((3)He,pγ)(14)N was measured in D((3)He) plasmas JET tokamak with ion cyclotron resonance heating tuned to fundamental harmonic (3)He. Intensities and detailed shapes were successfully reproduced using a physics model combining kinetics reacting ions description nuclear differential cross sections for populating L1-L8 (14)N excitation levels yielding observed emission. results provide paradigm, which...
To consolidate International Thermonuclear Experimental Reactor (ITER) design choices and prepare for its operation, Joint European Torus (JET) has implemented ITER's plasma facing materials, namely, Be the main wall W in divertor. In addition, protection systems, diagnostics, vertical stability control were upgraded heating capability of neutral beams was increased to over 30 MW. First results confirm expected benefits limitations all metal components (PFCs) but also yield understanding...
We report on a very efficient ion-cyclotron-resonance-frequency (ICRF) absorption scheme (Z)–Y–X, which hinges the presence of three ion species residing in plasma. A mode conversion (cutoff-resonance) layer is well known to appear two-ion plasmas. If location L-cutoff Y–X plasmas, can be controlled by varying Y : X density ratio, almost coincides with fundamental cyclotron resonance third Z (resonant absorber), latter—albeit present only trace quantities—is shown absorb all incoming RF...
Dedicated experiments to generate energetic D ions and fusion-born alpha particles were performed at the Joint European Torus (JET) with ITER-like wall (ILW). Using 3-ion radio frequency (RF) heating scenario, deuterium from neutral beam injection (NBI) accelerated in core of mixed plasmas higher energies ion cyclotron resonance (ICRF) waves, turn leading a core-localized source particles. The fast-ion distribution RF-accelerated D-NBI was controlled by varying ICRF NBI power ( 4–6 MW, 3–20...
Abstract JET experiments using the fuel mixture envisaged for fusion power plants, deuterium and tritium (D–T), provide a unique opportunity to validate existing D–T prediction capabilities in support of future device design operation preparation. The 2021 experimental campaign has achieved powers sustained over 5 s ITER-relevant conditions i.e. with baseline or hybrid scenario full metallic wall. In preparation campaign, extensive predictive modelling was carried out several assumptions...
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 Burning reactor plasmas will be self-heated by fusion born alpha particles from deuterium-tritium reactions. Consequently, a thorough understanding of the confinement and transport DT-born is necessary to maintain plasma self-heating. Measurements fast ion losses provide direct means monitor particle confinement. JET’s 2021–2022 second experimental DT-campaign offers burning scenarios with advanced loss diagnostics for first time in nearly 25 years. Coherent non-coherent were...
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 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...
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...
Abstract High-resolution γ-ray measurements were carried out on the Joint European Torus (JET) in an experiment aimed at accelerating 4 He ions MeV range by coupling third harmonic radio frequency heating to injected beam. For first time, Doppler broadening of peaks from 12 C(d, pγ) 13 C and 9 Be(α, nγ) reactions was observed interpreted with dedicated Monte Carlo codes based detailed nuclear physics processes. Information confined deuteron energy distribution inferred, energies as high 6...
This paper summarizes the operational experience of ion cyclotron resonant frequency (ICRF) ITER-like antenna on JET aiming at substantially increasing power density in range requirements for ITER combined with load resiliency. An in-depth description its commissioning, aspects and achieved performances is presented.
Recent achievements in studies of the effects ICRF (Ion Cyclotron Range Frequencies) power on SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) ASDEX Upgrade (AUG), Alcator C-Mod, JET-ILW are reviewed. Capabilities to diagnose model effect DC biasing associated impurity production at active antennas magnetic field connections described. The experiments show that near-fields can lead not only E × B convection, but also modifications density, which for C-Mod limited a narrow region...