Publications by Basil Duval | EPFL Graph Search

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The Tokamak à Configuration Variable has a unique Fast Ion Loss Detector (FILD) that allows the simultaneous measurement of co- and counter-current fast-ion losses in forward or reverse magnetic field. Recently, multiple novel upgrades have been implemente ...

Recent TCV experiments confirm the predicted formation of an electric potential well, below the magnetic X-point, in configurations with unfavorable

B_t

field direction (ion

\nabla B

drift away from the divertor), that substantially reshapes the typica ...

This work advances the quantitative validation of SOLPS-ITER against TCV ohmic L-mode discharges. It demonstrates that the treatment of the ion parallel heat-flux limiter and the assumptions adopted for chemical sputtering provide a consistent explanation for the divertor over-cooling and excessive divertor density predicted by earlier simulations. A systematic heat-flux-limiter scan highlights that a strong restriction of ion heat conduction significantly reduces both electron target temperatures T e,t and

A single chord, single processing chain, hybrid (analog/digital) pulse height analysis diagnostic has been developed for the TCV tokamak, aiming to provide the evolution of the plasma electron temperature with a software selectable minimum temporal resolut ...

Neutron emission spectroscopy is a diagnostic technique that allows for energy measurements of neutrons born in nuclear reactions. The JET tokamak fusion experiment (Culham, UK) has a special role in this respect as advanced spectrometers for 2.5 MeV and 1 ...

Bayesian integrated data analysis combines measurements from different diagnostics to jointly measure plasma parameters of interest such as temperatures, densities, and drift velocities. Integrated data analysis of fast-ion measurements has long been hampe ...

Particle tagging in a tokamak provides an attractive method for studying transport mechanisms. The injection of test particles at the plasma edge and the subsequent measurement of the evolution of their concentration at the centre can be used to quantify the underlying transport mechanisms. This has been carried out on the TCA tokamak by injecting hydrogen into a deuterium discharge and simultaneously measuring the temporal evolution of the central effective mass and the edge ionization rate.

Confinement in TCV electron cyclotron heated discharges was studied as a function of plasma shape, i.e. as a function of elongation, 1.1 < kappa < 2.15, and triangularity, -0.65 less than or equal to delta less than or equal to 0.55. The electron energy confinement time was found to increase with elongation, owing in part to the increase of plasma current with elongation. The beneficial effect of negative triangularities was most effective at low power and tended to decrease at the higher powers used. The l

Scientific and technical activities on JET focus on the issues likely to affect the ITER design and operation. Our understanding of the ITER reference mode of operation, the ELMy H-mode, has progressed significantly. The extrapolation of ELM size to ITER has been re-evaluated. Neoclassical tearing modes have been shown to be meta-stable in JET, and their beta limits can be raised by destabilization (modification) of sawteeth by ion cyclotron radio frequency heating (ICRH). Alpha simulation experiments with

The TCV tokamak has obtained ohmic H-modes in virtually all diverted plasmas with the ion del B drift directed towards an X-point and in several elongated limiter plasmas. Troyon factors (beta(tor)aB/l(p)) up to 2 and line average densities up to 2.2 x 10(20) m(-3), corresponding to the Greenwald limit, have been obtained in diverted ELM-free H-modes. Quasi-stationary H-modes lasting for the entire current flat top (1.5 s) have been obtained in the presence of regular ELMs. The occurrence and magnitude of E

The flux of charge exchange ( CX) neutrals measured by neutral particle analysers ( NPAs) is the line integral along the viewline of the NPA and contains information about the ion energy distribution of the observed plasma. On the Tokamaka a Configuration ...

Negative triangularity plasma configurations have been extensively studied in the Tokamak à Configuration Variable (TCV), and have displayed enhanced heat confinement for thermal electrons and ions. Herein, the question of fast-ion confinement is addressed. Limited negative (NT) and positive triangularity (PT) plasmas are compared. The plasma volume and position are kept the same between the discharges to match the neutral beam heating (NBI) deposition, isolating the effect of triangularity. These plasmas w

A comparative study of X- and O-mode high field side launch for electron cyclotron heating (ECH) breakdown and startup of tokamak plasmas has been performed. It is found that X-mode power is not absorbed at the cyclotron resonance but uniquely at the upper hybrid resonance, displaced to the low field side of the cyclotron resonance. O-mode power, however, is absorbed at the cyclotron resonance as well. The displacement of the upper hybrid resonance to the low field side with O-mode launch is significantly s

This paper presents the transport analysis of high density baseline discharges in the 2016 experimental campaign of the Joint European Torus with the ITER-Like Wall (JET-ILW), where a significant increase in the deuterium-deuterium (D-D) fusion neutron rat ...

A pedestal prediction model Europed is built on the existing EPED1 model by coupling it with core transport simulation using a Bohm-gyroBohm transport model to self-consistently predict JET-ILW power scan for hybrid plasmas that display weaker power degrad ...

The measurement of the energy spectra and densities of alpha-particles and other fast ions are part of the ITER measurement requirements, highlighting the importance of energy-resolved energetic-particle measurements for the mission of ITER. However, it ha ...

Post-disruption runaway electron (RE) beams in tokamaks with large current can cause deep melting of the vessel and are one of the major concerns for ITER operations. Consequently, a considerable effort is provided by the scientific community in order to t ...

The EUROfusion Work Package JET3 programme, established to enable the technological exploitation of the JET experiments over the next years, includes, within the NEXP subproject, a novel Shutdown Dose Rate (SDR) experiment. Considering its ITER-relevance, ...

This study employs the established momentum transport analysis at ASDEX Upgrade [Zimmermann et al., Nucl. Fusion 63, 124003 (2023)] to investigate the parametric variations of the momentum transport coefficients in the core of H-mode plasmas. These experim ...

Operation of the JET tokamak with beryllium and tungsten ITER-like wall provides unique opportunity for detailed studies on dust generation: quantity, morphology, location, etc. The programme carried out in response to ITER needs for safety assessment comp ...

Basil Duval

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Design and upgrades of the TCV fast ion loss detector

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

Advancing SOLPS-ITER validation with TCV L-mode discharges

Time resolved measurements by the pulse height analysis soft x-ray diagnostic on TCV

Neutron emission spectroscopy of D plasmas at JET with a compact liquid scintillating neutron spectrometer

Bayesian Integrated Data Analysis of Fast-Ion Measurements by Velocity-Space Tomography

Measurement of Hydrogen Transport in Deuterium Discharges Using the Dynamic-Response of the Effective Mass

Energy confinement and MHD activity in shaped TCV plasmas with localized electron cyclotron heating

Overview of JET results

Ohmic H-modes in the TCV tokamak

Reconstruction of ion temperature profiles from single chord NPA measurements on the TCV tokamak

Fast ion confinement in negative triangularity plasmas on the TCV tokamak

X-Mode and O-Mode Electron-Cyclotron Heating Breakdown and Startup in Tca

High fusion performance at high T-i/T-e in JET-ILW baseline plasmas with high NBI heating power and low gas puffing

Integrated modelling of H-mode pedestal and confinement in JET-ILW

Diagnostic of fast-ion energy spectra and densities in magnetized plasmas

Runaway electron beam control

Shutdown dose rate measurements after the 2016 Deuterium-Deuterium campaign at JET

Experimental validation of momentum transport theory in the core of H-mode plasmas in the ASDEX Upgrade tokamak

Dust generation in tokamaks: Overview of beryllium and tungsten dust characterisation in JET with the ITER-like wall