Publications de David Pfefferlé

Coordinate parameterisation and spectral method optimisation for Beltrami field solver in stellarator geometry

David Pfefferlé, Aravind Kumar Chandiran, Antoine Baillod, Ajay Kumar

The numerical solution of the stepped pressure equilibrium (Hudson et al 2012 Phys. Plasmas 19 112502) requires a fast and robust solver to obtain the Beltrami field in three-dimensional geometry such as stellarators. The spectral method implemented in the ...

2020

Identification of an Optimized Heating and Fast Ion Generation Scheme for the Wendelstein 7-X Stellarator

Jonathan Graves, Wilfred Anthony Cooper, David Pfefferlé, Hamish William Patten

A Doppler shifted resonance minority species ion cyclotron range of frequency (ICRF) scheme for heating neutral beam ions has been identified and optimized for theWendelstein 7-X stellarator. Compared with more conventional methods, the synergetic scheme i ...

2020

Validation of the BEAMS3D neutral beam deposition model on Wendelstein 7-X

Jonathan Graves, David Pfefferlé, Mike Machielsen, Adnan Ali, Yu Gao

The neutral beam deposition model in the BEAMS3D code is validated against neutral beam attenuation data from Wendelstein 7-X (W7-X). A set of experimental discharges where the neutral beam injection system of W7-X was utilized were reconstructed. These di ...

IOP Publishing Ltd2020

Determination of tungsten sources in the JET-ILW divertor by spectroscopic imaging in the presence of a strong plasma continuum

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Duccio Testa, Jonnathan Cesar Hidalgo Acosta, Jonathan Graves, Yves Martin, Li Shuai, Alberto Hernando de Castro

The identification of the sources of atomic tungsten and the measurement of their radiation distribution in front of all plasma-facing components has been performed in JET with the help of two digital cameras with the same two-dimensional view, equipped wi ...

Elsevier2019

Long-lived coupled peeling ballooning modes preceding ELMs on JET

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

In some JET discharges, type-I edge localised modes (ELMs) are preceded by a class of low-frequency oscillations (Perez et al 2004 Nucl. Fusion 44 609). While in many cases the ELM is triggered during the growth phase of this oscillation, it is also observ ...

IOP Publishing Ltd2019

EDGE2D-EIRENE simulations of the influence of isotope effects and anomalous transport coefficients on near scrape-off layer radial electric field

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Richard Pitts, Sun Hee Kim

EDGE2D-EIRENE (the 'code') simulations show that radial electric field, Er, in the near scrape-off layer (SOL) of tokamaks can have large variations leading to a strong local E x B shear greatly exceeding that in the core region. This was pointed out in si ...

2019

Measuring fast ions in fusion plasmas with neutron diagnostics at JET

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

Fast ions in fusion plasmas often leave characteristic signatures in the neutron emission from the plasma. In this paper, we show how neutron measurements can be used to study fast ions and give examples of physics results obtained on present day tokamaks. ...

2019

Comparison of the structure of the plasma-facing surface and tritium accumulation in beryllium tiles from JET ILW campaigns 2011-2012 and 2013-2014

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

In this study, beryllium tiles from Joint European Torus (JET) vacuum vessel wall were analysed and compared regarding their position in the vacuum vessel and differences in the exploitation conditions during two campaigns of ITER-Like-Wall (ILW) in 2011-2 ...

Elsevier2019

Micro ion beam analysis for the erosion of beryllium marker tiles in a tokamak limiter

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Henri Weisen, Joan Decker

Beryllium limiter marker tiles were exposed to plasma in the Joint European Torus to diagnose the erosion of main chamber wall materials. A limiter marker tile consists of a beryllium coating layer (7-9 mu m) on the top of bulk beryllium, with a nickel int ...

2019

Modelling of tungsten erosion and deposition in the divertor of JET-ILW in comparison to experimental findings

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Duccio Testa, Sun Hee Kim, Jonathan Graves, Yves Martin, Daniel Scott Alessi, Julio Rodriguez

The erosion, transport and deposition of tungsten in the outer divertor of JET-ILW has been studied for an H-Mode discharge with low frequency ELMs. For this specific case with an inter-ELM electron temperature at the strike point of about 20 eV, tungsten ...

Elsevier2019