Publications associées à Progress on the ITER ECRH upper launcher steering mirror identification and control

A machine-learning-based tool for last closed-flux surface reconstruction on tokamaks

Olivier Sauter, Alessandro Pau, Chenguang Wan, Xiaojuan Liu

Tokamaks allow to confine fusion plasma with magnetic fields. The prediction/reconstruction of the last closed-flux surface (LCFS) is one of the primary challenges in the control of the magnetic configuration. The evolution in time of the LCFS is determine ...

IOP Publishing Ltd2023

Modeling of saturated external MHD instabilities in tokamaks: A comparison of 3D free boundary equilibria and nonlinear stability calculations

Jonathan Graves

3D free boundary equilibrium computations have recently been used to model external kinks and edge harmonic oscillations (EHOs), comparing with linear MHD stability codes, and nonlinear analytic theory [Kleiner et al., Phys. Plasma Controlled Fusion 61, 08 ...

2022

Self-consistent simulation of multi-component plasma turbulence and neutral dynamics in the tokamak boundary

André Calado Coroado

The interaction between neutral particles and the plasma plays a key role in determining the dynamics of the tokamak boundary that, in turn, significantly impact the overall performance of the device. Leveraging the work in Wersal and Ricci [Nucl. Fusion 5 ...

EPFL2021

Parallel convection and E × B drifts in the TCV snowflake divertor and their effects on target heat-fluxes

Basil Duval, Holger Reimerdes, Joaquim Loizu Cisquella, Cedric Kar-Wai Tsui, Roberto Maurizio, Mirko Wensing, Davide Galassi

Parallel convection and E × B drifts act together to redistribute heat between the strike-points mechanisms is enhanced near the secondary X-point and is shown to dominate over heat in the low field side snowflake minus (LFS SF−). The cumulative heat conve ...

IOP Publishing Ltd2021

The impact of anisotropy on ITER scenarios

Olivier Sauter

We report on the impact of anisotropy to tokamak plasma configuration and stability. Our focus is on analysis of the impact of anisotropy on ITER pre-fusion power operation 5 MA, B = 1.8 T ICRH scenarios. To model ITER scenarios remapping tools are develop ...

IOP Publishing Ltd2020

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

LTCC magnetic sensors at EPFL and TCV: Lessons learnt for ITER

Thomas Maeder, Pierre Lavanchy, Jonathan Bryan Lister, Xavier Llobet, Blaise Marlétaz, Philippe Marmillod, Matthias Garcin, Ugo Siravo, Caroline Jacq, Christian Moura, Duccio Testa, Frédéric Dolizy, Severino Antonioni, Matthieu Toussaint, Steve Couturier, Adrien Aymeric Thibault Corne, Aylwin Iantchenko, Lorenzo Stipani

Innovative 3D high-frequency magnetic sensors have been designed and manufactured in-house for installation on the Tokamak a Configuration Variable (TCV), and are currently routinely operational. These sensors combine the Low Temperature Co-fired Ceramic ( ...

2019

Properties of a new quasi-axisymmetric configuration

Joaquim Loizu Cisquella

A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-particle losses and is stable to ideal magnetohydrodynamic (MHD) instabilities. The design has fast-particle loss rates below 8% for flux surfaces within the half-radiu ...

IOP Publishing Ltd2019

Tokamak Edge Plasma Turbulence Interaction with Magnetic X-Point in 3D Global Simulations

Eric Serre, Davide Galassi

Turbulence in the edge plasma of a tokamak is a key actor in the determination of the confinement properties. The divertor configuration seems to be beneficial for confinement, suggesting an effect on turbulence of the particular magnetic geometry introduc ...

2019

Helical equilibrium magnetohydrodynamic flow effects on the stability properties of low-n ideal external-infernal modes in weak shear tokamak configurations

Wilfred Anthony Cooper, Jonathan Graves, Patrycja Nowak-Sliwinska, Daniele Brunetti, Alberto Mariani

The impact of equilibrium helical flows on the stability properties of low shear tokamak plasmas is assessed. The corrections due to such helical flow to the equilibrium profiles (mass density, pressure, Shafranov shift, magnetic fluxes) are computed by mi ...

IOP PUBLISHING LTD2019

Optimized up-down asymmetry to drive fast intrinsic rotation in tokamaks

Justin Richard Ball

Breaking the up-down symmetry of the tokamak poloidal cross-section can significantly increase the spontaneous rotation due to turbulent momentum transport. In this work, we optimize the shape of flux surfaces with both tilted elongation and tilted triangu ...

IOP Publishing Ltd2018

Poloidal CX visible light plasma rotation diagnostics in TCV

Claudio Marini

Controlled thermonuclear fusion is the main goal of plasma physics. At the Swiss Plasma Center, the Tokamak `a Configuration Variable (TCV) constitutes the main experiment on fusion research, where high temperature plasmas are confined by means of magneti ...

EPFL2017

Outer midplane scrape-off layer profiles and turbulence in simulations of Alcator C-Mod inner-wall limited discharges

Federico David Halpern

A region of steep plasma gradients, the so-called "narrow-feature," has been found in the near scrape-off layer (SOL) of inner-wall limited (IWL) discharges. Dedicated IWL discharges were carried out in Alcator C-Mod [Marmar et al., Nucl. Fusion 55, 104020 ...

Amer Inst Physics2017

Scrape-Off Layer physics in limited plasmas in TCV

Federico Nespoli

Controlled nuclear fusion is the most promising candidate for being an inexhaustible, clean and intrinsically safe energy source. In the tokamak fusion reactor concept, a high temperature plasma is confined by magnetic fields. Turbulence diffuses the confi ...

EPFL2017

Poloidal asymmetry in the narrow heat flux feature in the TCV scrape-off layer

Basil Duval, Ivo Furno, Holger Reimerdes, Stefano Coda, Jan Horacek, Benoît Labit, Joaquim Loizu Cisquella, Paolo Ricci, Christian Gabriel Theiler, Federico David Halpern, Federico Nespoli, Cedric Kar-Wai Tsui

Heat flux profiles inferred from a reciprocating probe at the outer midplane of the TCV tokamak during inner wall limited discharges feature radial fall-off lengths that shorten near the last closed flux surface (LCFS) consistent with the so-called narrow ...

American Institute of Physics (AIP)2017

Energetic ion dynamics and confinement in 3D saturated MHD configurations

David Pfefferlé

In the following theoretical and numerically oriented work, a number of findings have been assembled. The newly devised VENUS-LEVIS code, designed to accurately solve the motion of energetic particles in the presence of 3D magnetic fields, relies on a non- ...

EPFL2015

Poloidal asymmetries in edge transport barriers

Christian Gabriel Theiler

Measurements of impurities in Alcator C-Mod indicate that in the pedestal region, significant poloidal asymmetries can exist in the impurity density, ion temperature, and main ion density. In light of the observation that ion temperature and electrostatic ...

Amer Inst Physics2015

Hybrid guiding-centre/full-orbit simulations in non-axisymmetric magnetic geometry exploiting general criterion for guiding-centre accuracy

Wilfred Anthony Cooper, Jonathan Graves, David Pfefferlé

To identify under what conditions guiding-centre or full-orbit tracing should be used, an estimation of the spatial variation of the magnetic field is proposed, not only taking into account gradient and curvature terms but also parallel currents and the lo ...

Iop Publishing Ltd2015

Impact of RMP magnetic field simulation models on fast ion losses

Wilfred Anthony Cooper, Jonathan Graves, David Pfefferlé, Cyril Misev

Two opposing approaches to include resonant magnetic perturbations (RMPs) in fast ion simulations are compared, one where the vacuum field caused by the RMP current coils is added to the axisymmetric MHD equilibrium, the other where the MHD equilibrium inc ...

International Atomic Energy Agency2014

Basic characterization of TORPEX electrostatic modes in closed field line configurations

Ambrogio Fasoli, Ivo Furno, Sébastien Jolliet, Paolo Ricci, Fabio Avino

Electrostatic coherent modes are studied in the TORPEX device [Fasoli et al., Plasma Phys. Controlled Fusion 52, 124020 (2010)], in closed flux surfaces. The accessibility to this magnetic geometry is provided by a current-carrying in-vessel toroidal condu ...

Amer Inst Physics2014