A. Kappatou
A5011531774- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- High-Energy Particle Collisions Research
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Nuclear Materials and Properties
- Fluid Dynamics and Turbulent Flows
- Hydrogen Storage and Materials
- Particle physics theoretical and experimental studies
- Air Quality Monitoring and Forecasting
- High voltage insulation and dielectric phenomena
- Machine Learning and ELM
- Particle Accelerators and Free-Electron Lasers
- Anomaly Detection Techniques and Applications
Max Planck Institute for Plasma Physics
2016-2025
CEA Cadarache
2023
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2023
Max Planck Society
2015-2021
Royal Military Academy
2020
Dutch Institute for Fundamental Energy Research
2012-2017
Fusion (United States)
2015
Fusion Academy
2015
Institute for Atomic and Molecular Physics
2013
Eindhoven University of Technology
2013
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...
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 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 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 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...
At ASDEX upgrade (AUG) a new framework for the evaluation of impurity densities based on measurements from charge exchange recombination spectroscopy (CXRS) diagnostics has been developed. The concentration analysis code, or CHICA, can perform these calculations all beam-based CXRS at AUG and is equipped with atomic data regularly measured spectral lines (He, Li, B, C, N, O, Ne). CHICA includes four different methods neutral density populations, which feature implementations contain varying...
The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (W7-X), highly flexible and extensive CXRS been built to provide high-resolution local measurements of several important plasma parameters using recently commissioned neutral beam heating. This paper outlines design specifics W7-X system gives examples initial results obtained, including typical...
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 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 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...
Abstract Extrapolating the observed behavior of helium exhaust in current tokamaks towards future reactors requires understanding underlying physical mechanisms determining transport, recycling and pumping. Helium compression is main physics-based figure merit characterizing how efficiently transported divertor recycled at target plates. Moreover, gas transport subdivertor region pumps strongly influenced by vessel geometry installed pumps.&#xD;The SOLPS-ITER code package used to model...
A new core charge exchange recombination spectroscopy diagnostic has been installed in the ASDEX Upgrade tokamak that is capable of measuring impurity ion temperature, toroidal rotation, and density on both low field side (LFS) high (HFS) plasma. The system features 48 lines-of-sight (LOS) with a radial resolution varies from ±2 cm LFS down to ±0.75 HFS sufficient signal run routinely at 10 ms for special circumstances 2.5 integration time. LFS-HFS temperature profiles provide an additional...
Abstract Screening of high-Z (W) impurities from the confined plasma by temperature gradient at periphery fusion-grade H-mode plasmas has been demonstrated in JET-ILW (ITER-like wall) tokamak. Through careful optimisation hybrid-scenario, deuterium with sufficient heating power ( <?CDATA $\gtrsim$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≳</mml:mo> </mml:math> 32 MW), high enough ion gradients pedestal top can be achieved for collisional,...
Abstract We study localized edge turbulence in the ASDEX Upgrade tokamak that appears if resonant magnetic perturbations (RMP) are applied to suppress modes (ELMs) high confinement mode. The concomitant density fluctuations detected by microwave reflectometry at outboard midplane. Two can be distinguished, (a) a broadband fluctuation below threshold of RMP field amplitude, and (b) narrow-band quasi-coherent mode (QCM) above threshold. is toroidally spread out but disappears toroidal position...
Abstract This work applies the coupled JINTRAC and QuaLiKiz-neural-network (QLKNN) model on ohmic current ramp-up phase of a JET D discharge. The chosen scenario exhibits hollow <?CDATA $T_\mathrm{e}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">e</mml:mi> </mml:mrow> </mml:msub> </mml:math> profile attributed to core impurity accumulation, which is observed worsen with increasing fuel ion...
Recent improvements to the heating and diagnostic systems on ASDEX Upgrade tokamak allow renewed investigations into non-inductive operation scenarios with improved confinement in a full-metal device.Motivated by this, scenario β N ≈ 2.7, q 95 5.3 high current fraction f NI 90% has been developed.The offers good H 98 (y, 2) > 1.1 normalised ion temperature gradients R/L T i 12.Moreover, it is robust against resistive magnetohydrodynamic (MHD) instabilities, but does suffer from ideal MHD...
The medium size divertor tokamak ASDEX Upgrade (major and minor radii 1.65 m 0.5 m, respectively, magnetic-field strength 2.5 T) possesses flexible shaping versatile heating current drive systems. Recently the technical capabilities were extended by increasing electron cyclotron resonance (ECRH) power, installing 2 × 8 internal magnetic perturbation coils, improving ion range of frequency compatibility with tungsten wall. With reliable suppression large type-I edge localized modes (ELMs)...
Understanding the dependence of H-mode power threshold, on main ion composition is crucial for operation in ITER. In this work, threshold studies conducted at ASDEX Upgrade are presented. These were performed hydrogen plasmas with helium doping and mixed hydrogen-deuterium plasmas. stays constant level pure up to . Power balance calculations transport code ASTRA show that edge heat flux L-H transition independent concentration applied auxiliary heating, supporting a critical needed enter...
Abstract This work studies the influence of radio frequency (RF) waves in ion cyclotron resonance heating (ICRH) range frequencies on fusion alphas during recent JET D-T campaign. Fusion from reactions are created with energies about 3.5 MeV and therefore have significant Doppler shifts enabling synergistic interactions between them RF at a broad frequencies, including ones foreseen for future machines ITER (Schneider et al 2021 Nucl. 61 126058) SPARC (Creely 2020 J. Plasma Phys. 86...
Abstract The paper presents experimental and modelling results of a comparison negative (NT) positive (PT) triangularity ASDEX Upgrade (AUG) discharges using the plasma shapes presently foreseen in DTT tokamak, under construction Italy. This work is part broader effort investigation to understand whether good properties observed NT scenarios DIII-D TCV may be extrapolated device more generally DEMO future operations. have shown practical gain running these AUG plasmas with only ECRH mixed...