Concept

Classical diffusion

Publications associées (27)

Comparable levels of turbulent and neoclassical transport of high-Z impurities: integrated modelling in AUG, JET and C-Mod

Operation with beam heating is prone to central accumulation of high-Z impurities in present-day tokamaks due to a dominant neoclassical pinch. Fusion reactors are expected to have a different core transport regime for high-Z impurities, where turbulent transport completely dominates in both diffusion and convection, causing flat impurity profiles. In this work, we present integrated simulations of plasmas that approach this regime of less dominant neoclassical and stronger turbulent high-Z impurity transpo

IOP Publishing Ltd2026

Towards Digital Twins of Fusion Systems

Bridging the gap to next-step devices – while saving valuable time and resources – requires more than semi-empirical models, which struggle to predict plasma behavior in unexplored parameter regimes. Instead, validated simulation tools are essential, leveraging high-fidelity exascale computing and multi-fidelity models, including AI-based surrogates. To address these challenges, the “EUROfusion Theory and Advanced Simulation Coordination (E-TASC)” initiative was launched in 2021. It includes 15 TSVV (Theory

IOP Publishing Ltd2026

Thermal helium beam measurements of plasma edge turbulence in positive and negative triangularity plasmas on TCV

Olivier Sauter, Stefano Coda

Edge plasma behaviour plays a central role in determining the overall confinement and operational limits of tokamak plasmas. In particular, turbulence at the plasma boundary strongly influences particle and heat transport and remains a key target for performance optimization. Among the shaping strategies currently explored, negative triangularity (NT) operation has emerged as a viable alternative to conventional positive triangularity (PT) plasmas, having demonstrated improved confinement, reduced turbulenc

IOP Publishing2026

Data-driven Model Order Reduction for Accelerating Boundary Plasma Turbulence Simulations

Simone Deparis

Machine learning (ML)-driven reduced-order modelling is applied to accelerate steady-state convergence in three-dimensional, nonlinear, flux-driven two-fluid simulations of boundary plasma turbulence. A parametric scan of plasma resistivity, heating and density sources is performed to generate comprehensive datasets across various turbulent regimes for model training and validation. To efficiently manage and interpret these datasets, we apply the proper orthogonal decomposition technique to reduce the dimen

CAMBRIDGE UNIV PRESS2026

Acceleration of Solvers for Plasma Simulation in the Tokamak Boundary

Simulating turbulence in the tokamak boundary, which is crucial for understanding and optimizing future fusion power plants performance, is computationally challenging due to the complex, multi-physics, and multi-scale nature of plasma dynamics. In the boundary region, plasma interacts with neutral particles recycled from the walls, leading to nonlinear phenomena that control confinement and heat exhaustion. Accurately capturing these coupled processes requires solving large-scale, stiff, and non-local pro

EPFL2026

Simulation of boundary plasma turbulence with realistic wall geometry

The GBS code (Ricci et al 2012 Plasma Phys. Control Fusion 54 124047) for boundary plasma turbulence is extended to handle flexible first wall geometry. This capability is enabled by the use of a finite difference scheme on a curvilinear structured grid. Grid generation and optimization leverage a spline-based elliptic grid generation framework originally developed in the context of isogeometric analysis applications (Hinz and Buffa 2024 Eng. Comput. 40, 3735-3764). First turbulence simulations of the Tokam

IOPScience2025

Simulation of boundary plasma turbulence with realistic first wall geometries

Divertor closure is expected to contribute to higher divertor neutral pressures. Higher neutral pressures are associated with facilitated access to a detached regime as well as higher power dissipation along the divertor legs, thereby making the regime attractive for future reactors. Experimentally, the effect of neutral pressure in the divertor has been investigated in devices such as Alcator C-mod, DIII-D, ASDEX Upgrade, MAST-U and TCV. Transport models for boundary plasmas and neutrals dynamics, such as

2025

Coupling transport simulations with Phase-Space-Reconstruction methods and Lyapunov exponents analyses

Nuclear fusion in tokamaks represents a promising solution for producing clean and sustainable energy. However, achieving stable and reliable operation requires controlling plasma dynamics over long periods. A crucial part of this challenge lies in the ability to predict plasma behavior from limited measurements, in order to anticipate and mitigate potential instabilities. In this context, it is particularly useful to develop tools that can evaluate the predictability horizon of a dynamic system, that is, t

EPFL2025

Modelling of advanced three-ion ICRF heating and fast ion generation scheme for tokamaks and stellarators

Jonathan Graves, Laurent Villard, Wilfred Anthony Cooper, David Pfefferlé, Jonathan Marc Philippe Faustin, Samuel Lanthaler

Absorption of ion-cyclotron range of frequencies waves at the fundamental resonance is an efficient source of plasma heating and fast ion generation in tokamaks and stellarators. This heating method is planned to be exploited as a fast ion source in the We ...

2017

Conceptual design and proof-of-principle testing of the real-time multispectral imaging system MANTIS

Basil Duval, Yanis Andrebe, Wouter Vijvers

The Multispectral Advanced Narrowband Tokamak Imaging System (MANTIS) is proposed to resolve the steep temperature and density gradients in the scrape-off layer of tokamaks in real-time. The initial design is to deliver two-dimensional distributions of key ...

Iop Publishing Ltd2017

Design of tangential viewing phase contrast imaging for turbulence measurements in JT-60SA

Stefano Coda

A tangential viewing phase contrast imaging system is being designed for the JT-60SA tokamak to investigate microturbulence. In order to obtain localized information on the turbulence, a spatial-filtering technique is applied, based on magnetic shearing. T ...

Amer Inst Physics2016

Cold pulse and rotation reversals with turbulence spreading and residual stress

Ning Yan

Transport modeling based on inclusion of turbulence spreading and residual stresses shows internal rotation reversals and polarity reversal of cold pulses, with a clear indication of nonlocal transport effects due to fast spreading in the turbulence intens ...

American Institute of Physics (AIP)2016

High density experiments in TCV ohmically heated and L-mode plasmas

Olivier Sauter, Basil Duval, Stefano Coda, Timothy Goodman, Benoît Labit, Laurie Porte, Alexander Karpushov, Antoine Pochelon, Roland Behn

Recent experiments have been performed on the Tokamak a configuration variable (TCV) to investigate the confinement properties of high density plasmas and the mechanism behind the density limit. In a limiter configuration with plasma elongation kappa = 1.3 ...

Iop Publishing Ltd2015

Theory framework for scrape-off layer turbulence in limited tokamaks

In the present work we address the physical mechanisms determining the SOL width of a simple inner-wall limited (IWL) configuration. This seemingly simple configuration has important implications for ITER start-up plasmas, and has triggered an important ITPA-sponsored effort. In the past few years, we have developed a thorough computational and analytical understanding of the physical processes regulating the IWL-SOL width. Our investigations are aided by 3D global, flux driven simulations of SOL turbulence

2014

Achieving and sustaining advanced scenarios in ITER modelled by CRONOS and DINA-CH

Jonathan Bryan Lister, Javier García Hernández, Karim Besseghir

The heating and current drive characteristics for accessing advanced scenarios in ITER, close to those obtained in present-day experiments, are analysed together with the plasma performance using the prescribed-boundary CRONOS suites of codes. For the hybr ...

Iop Publishing Ltd2013

Global electromagnetic simulations of tokamak scrape-off layer turbulence

Sébastien Jolliet

We discuss recent studies addressing the properties of tokamak SOL turbulence using a global, electromagnetic, fluid drift-reduced Braginskii model. Non-linear simulations are carried out using the Global Braginskii Solver (GBS) code [1], which is capable of carrying out self-consistent, global three-dimensional simulations of the plasma dynamics in the tokamak SOL. The simulations involve plasma profile formation in the SOL as a power balance between plasma flux from the core, the turbulent radial transpor

2013

Non-linear model-based optimization of actuator trajectories for tokamak plasma profile control

Olivier Sauter, Federico Alberto Alfredo Felici

A computational method is presented to determine the tokamak actuator time evolution (trajectories) required to optimally reach a given point in the tokamak operating space while satisfying a set of constraints. Usually, trajectories of plasma auxiliary he ...

2012

Ideal MHD spectrum calculations for the ARIES-CS configuration

Wilfred Anthony Cooper

Ideal MHD stability calculations for the ARIES compact stellarator (ARIES-CS) reactor design (Najmabadi et al 2008 Fusion Sci. Technol. 54 655) show a spectrum of instabilities. The ARIES design considered is a three field-period stellarator with engineeri ...

IOP Publishing Ltd2011

Transport and turbulence reduction with negative triangularity : Correlation ECE measurements in TCV

Olivier Sauter, Stefano Coda, Basil Duval, Timothy Goodman, Laurent Villard, Antoine Pochelon, Jean-Marc Moret, Roland Behn, Alberto Bottino, Philippe Marmillod, Sébastien Jolliet

Turbulence and Transport Reduction with Negative Triangularity : Correlation ECE Measurements in TCV Due to turbulence, core energy transport in fusion devices such as tokamaks generally exceeds collisional transport by at least an order of magnitude. It is therefore crucial to understand the instabilities driving the turbulent state and to find ways to control them. Plasma shape is one of these fundamental tools. In low collisionality plasmas, such as in a reactor, changing the plasma shape from Dee-shape

2010

Turbulence and transport reduction with innovative plasma shapes in TCV - correlation ECE measurements and gyrokinetic simulations

Antoine Pochelon

Turbulence and transport reduction with innovative plasma shapes in TCV -- correlation ECE measurement and gyrokinetic simulations Due to turbulence, core energy transport in tokamaks generally exceeds collisional transport by at least an order of magnitude. It is therefore crucial to understand the instabilities driving the turbulent state and to find ways to control them. Shaping the plasma is one of these fundamental tools. In low collisionality plasmas, such as in a reactor, changing triangularity from

2010

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Publications associées (27)

Comparable levels of turbulent and neoclassical transport of high-Z impurities: integrated modelling in AUG, JET and C-Mod

IOP Publishing Ltd2026

Turbulence and transport reduction with innovative plasma shapes in TCV - correlation ECE measurements and gyrokinetic simulations

Antoine Pochelon

2010