A5081608139- 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
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- High-Energy Particle Collisions Research
- Solar and Space Plasma Dynamics
- Physics of Superconductivity and Magnetism
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Electrostatic Discharge in Electronics
- Meteorological Phenomena and Simulations
- Nuclear Physics and Applications
- Particle physics theoretical and experimental studies
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Chemical Physics Studies
- High-pressure geophysics and materials
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
- Electron and X-Ray Spectroscopy Techniques
- Fluid Dynamics and Turbulent Flows
National Agency for New Technologies, Energy and Sustainable Economic Development
2004-2025
Institute of Plasma Physics
2012-2024
Institute for the Science and Technology of Plasmas
2019-2024
Max Planck Institute for Plasma Physics
2003-2024
National Academies of Sciences, Engineering, and Medicine
2015-2024
National Research Council
2010-2022
University of Milano-Bicocca
2022
Culham Science Centre
1993-2017
Max Planck Society
2014-2017
Culham Centre for Fusion Energy
2016-2017
Abstract Progress in physics understanding and theoretical model development of plasma transport confinement (TC) the ITPA TC Topical Group since publication ITER Physics Basis (IPB) document (Doyle et al 2007 Nucl. Fusion 47 S18) was summarized focusing on contributions to burning prediction control. This paper provides a general streamlined overview advances that were mainly led by joint experiments activities for last 15 years (see JEX/JA table appendix). starts with scientific strategy...
Experiments in the JET tokamak with additional heating power (ion cyclotron resonance and/or neutral beam injection) above 5 MW show that plasma can undergo a transition to new regime. In this regime, sawtooth instability is suppressed for periods up 1.6 s and level of long-wavelength, coherent MHD activity very low. An improvement global energy confinement time 20% observed. Possible mechanisms stabilization m=1 implications near-ignition regime are discussed.Received 26 May...
Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor reducing tokamak microturbulence, augmenting significantly the thermal stabilization. Based on nonlinear gyrokinetic simulations investigating set of ion heat transport experiments JET tokamak, described Mantica et al. [Phys. Rev. Lett. 107, 135004 (2011)], this result explains experimentally observed flux and stiffness reduction. These findings are expected...
This paper is an overview of recent results relating to turbulent particle and heat transport, the triggering internal transport barriers (ITBs). The dependence pinch velocity on plasma parameters has been clarified compared with experiment. Magnetic shear collisionality are found play a central role. Analysis made progress along two directions: dimensionless scaling laws, which agree prediction for electrostatic turbulence, analysis modulation experiments, provide stringent test models....
The behaviour of tungsten in the core hybrid scenario plasmas JET with ITER-like wall is analysed and modelled a combination neoclassical gyrokinetic codes. In these discharges, good confinement conditions can be maintained only for first 2?3?s high power phase. Later W accumulation regularly observed, often accompanied by onset magneto-hydrodynamical activity, particular tearing modes (NTMs), both which have detrimental effects on global energy confinement. dynamics process examined, taking...
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...
Toroidal momentum transport mechanisms are reviewed and put in a broader perspective. The generation of finite flux is closely related to the breaking symmetry (parity) along field. argument allows for systematic identification possible mechanisms. Those that appear lowest order normalized Larmor radius (the diagonal part, Coriolis pinch, E × B shearing, particle flux, up–down asymmetric equilibria) reasonably well understood. At higher order, expected be importance plasma edge, theory still...
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....
Abstract The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and preparation operation, as well addressing issues for a future DEMO design. Since 2015, AUG equipped with new pair 3-strap ICRF antennas, which were designed reduction tungsten release during operation. As predicted, factor two on ICRF-induced W plasma content could be achieved by sheath voltage at antenna limiters via compensation image currents central side straps in...
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 Plasmas with negative triangularity (NT) shape have been recently shown to be able achieve H-mode levels of confinement in L-mode, avoiding detrimental edge localised modes. Therefore, this plasma geometry is now studied as a possible viable option for future fusion reactor. Within framework, an NT under investigation the full power scenario Divertor Tokamak Test (DTT) facility, construction Italy, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...
Particle transport in magnetized plasmas is investigated with a fluid model of drift wave turbulence. An analytical calculation shows that magnetic field curvature and thermodiffusion drive an anomalous pinch. The driven pinch velocity consistent the prediction turbulence equipartition theory. flux found to be directed inward for small ratio electron ion pressure gradient, it reverses its sign when increasing this ratio. Numerical simulations confirm turbulent particle exists. It mainly by...
This paper analyses the properties of a critical gradient transport model based on few assumptions: electrostatic gyroBohm scaling law, existence an instability threshold and finite background below threshold. A quantitative criterion stiffness is proposed, which provides means for assessment inter-machine comparison. It also shown that this compatible with two-term law global confinement, as proposed recently by International Tokamak Physics Activity–Confinement Data Base Modelling Topical...
For the first time, scalings for density peaking in tokamaks are obtained from a database consisting of observations two devices, ASDEX Upgrade and JET. The investigation relies on an inversion method interferometer signals which grants consistent reconstructions despite differences geometries. By combining these correlations between physics parameters investigated their role determining reduced. Multiple regression analyses show that combined collisionality is most relevant parameter....
Recent developments in theory-based modelling of core heavy impurity transport are presented, and shown to be necessary for quantitative description present experiments JET ASDEX Upgrade. The treatment impurities is complicated by their large mass charge, which result a strong response plasma rotation or any small background electrostatic field the plasma, such as that generated anisotropic external heating. These forces lead poloidal asymmetries density, have recently been added numerical...
The impact of electromagnetic stabilization and flow shear on ITG turbulence is investigated. Analysis a low-$\beta$ JET L-mode discharge illustrates the relation between stabilization, proximity to instability threshold. This threshold reduced by suprathermal pressure gradients, highlighting effectiveness fast ions in stabilization. Extensive linear nonlinear gyrokinetic simulations are then carried out for high-$\beta$ hybrid 75225, at two separate locations inner outer radii. It found...
The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect central electron on impurities such as Ni and Mo in H-mode low collisionality discharges JET. transport parameters have measured by introducing a transient perturbation their densities via laser blow off technique. Without ICRH density profiles are typically peaked. application induces plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional...
A new technique has been developed to produce plasmas with improved confinement relative the H98,y2 scaling law (ITER Physics Expert Groups on Confinement and Transport Modelling Database ITER Basics Editors EDA 1999 Nucl. Fusion 39 2175) JET tokamak. In mid-size tokamaks ASDEX upgrade DIII-D heating during current formation is used a flat q-profile minimum close 1. On this leads q-profiles similar q but opposite other not an state. By changing method utilizing faster ramp temporary higher...
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...
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 In recent years tokamak experiments and modelling have increasingly indicated that the interaction between suprathermal (fast) ions thermal plasma can lead to a reduction of turbulence an improvement confinement. The regimes in which this stabilization occurs are relevant burning plasmas, their understanding will inform reactor scenario optimization. This review summarizes observations, simulations, theoretical understanding, open questions on emerging topic.
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...
Electron transport in tokamaks has many different features which are briefly reviewed. The paper is focused on electron heat conventional tokamak plasmas. An inter-machine comparison indicates that the non-dimensional gradient length of temperature profiles R/LTe almost independent devices and varies little with plasma parameters. This strongly suggests governed by turbulence a threshold R/LTe. confirmed modulation experiments using cyclotron heating. Simulations empirical physics-based...
Experiments with strong localized electron cyclotron heating (ECH) in the RTP tokamak show that heat transport is governed by alternating layers of good and bad thermal conduction. For central deposition hot filaments are observed inside q = 1 radius. Moving ECH resonance from centre to edge plasma results discrete steps temperature. The transitions occur when minimum value crosses 1,2,5/2 or 3, correspond loss a barrier situated close rational value. Close new type sawtooth activity...