Recherche

Afficher tous les résultats pour

Accueil

Personne

Stephan Brunner

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (128)

Page 4 sur 7

Collisionless microtearing modes in hot tokamaks: Effect of trapped electrons

Laurent Villard, Stephan Brunner

Collisionless microtearing modes have recently been found linearly unstable in sharp temperature gradient regions of large aspect ratio tokamaks. The magnetic drift resonance of passing electrons has been found to be sufficient to destabilise these modes a ...

Amer Inst Physics2015

A Quasilinear Model for Momentum Transport Including Rotation and Electron-scale Turbulence

Stephan Brunner, Justin Richard Ball, Haomin Sun

In a previous paper, a new gyrokinetic quasilinear model was proposed to study turbulent momentum transport in tokamaks with up-down asymmetric plasma shaping and toroidal flow shear (Sun et al 2024 Nuclear Fusion 64 036026). In this work, we start by appl ...

IOP Publishing Ltd2025

Global Nonlinear Electromagnetic Simulations of Tokamak Turbulence

Laurent Villard, Stephan Brunner, Trach-Minh Tran, Alberto Bottino, Sébastien Jolliet, Ben McMillan, Thibaut Vernay

The particle-in-cell code ORB5 is a global gyrokinetic turbulence simulation code in tokamak geometry. It has been developed at CRPP, Lausanne, Switzerland, with major contributions from IPP, Garching, Germany, and IPP, Greifswald, Germany, under a long-st ...

Institute of Electrical and Electronics Engineers2010

Prediction of the Inter-Node Communication Costs of a New Gyrokinetic Code with Toroidal Domain

Laurent Villard, Stephan Brunner, Emmanuel Lanti, Noé Thomas Elie Ohana, Claudio Gheller, Aaron Lewis Scheinberg

We consider the communication costs of gyrokinetic plasma physics simulations running at large scale. For this we apply virtual decompositions of the toroidal domain in three dimensions and additional domain cloning to existing simulations done with the OR ...

SPRINGER INTERNATIONAL PUBLISHING AG2018

Gyrokinetic turbulence modeling of a high performance scenario in JT-60SA

Stefano Coda, Stephan Brunner, Aylwin Iantchenko

Local gyrokinetic simulations are used to model turbulent transport for the first time in a representative high-performance plasma discharge projected for the new JT-60SA tokamak. The discharge features a double-null separatrix, 41 MW of combined neutral b ...

IOP Publishing Ltd2024

Moment-based approach to the flux-tube linear gyrokinetic model

Paolo Ricci, Stephan Brunner

This work reports on the development and numerical implementation of the linear electromagnetic gyrokinetic (GK) model in a tokamak flux-tube geometry using a moment approach based on the expansion of the perturbed distribution function on a velocity-space ...

Cambridge University Press2023

Synergy between ion temperature gradient turbulence and neoclassical processes in global gyrokinetic particle-in-cell simulations

Laurent Villard, Stephan Brunner, Trach-Minh Tran, Alberto Bottino, Sébastien Jolliet, Ben McMillan, Thibaut Vernay

Based on the CYCLONE case, simulations of collisional electrostatic ion temperature gradient (ITG) microturbulence carried out with the global gyrokinetic particle-in-cell (PIC) code ORB5 are presented. Considering adiabatic electrons, an increase in ion h ...

American Institute of Physics (AIP)2012

Kinetic Theory and Vlasov Simulation of Nonlinear Ion-Acoustic Waves in Multi-Ion Species Plasmas

Stephan Brunner

The theory of damping and nonlinear frequency shifts from particles resonant with ion-acoustic waves (IAWs) is presented for multi-ion species plasma and compared to driven wave Vlasov simulations. Two distinct IAW modes may be supported in multi-ion speci ...

Amer Physical Soc2013

A synthetic phase-contrast imaging diagnostic with spatial filtering for gyrokinetic simulations

Stefano Coda, Stephan Brunner, Gabriele Merlo, Justin Richard Ball, Aylwin Iantchenko

A Phase-contrast imaging (PCI) diagnostic provides measurements of line-integrated electron density fluctuations. Localisation along the laser beam path can be achieved with a spatial filter that selects the wave-vector directions of the fluctuations contr ...

2023

Overview of the TCV tokamak experimental programme

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Henri Weisen, Timothy Goodman, Yves Martin, Stefano Alberti, Duccio Testa, Jean-Marc Moret, Ivo Furno, Patrick Blanchard, Benoît Labit, Jan Horacek, Paolo Ricci, Jean-Philippe Hogge, Jonathan Graves, Stephan Brunner, Holger Reimerdes, Laurie Porte, Christian Gabriel Theiler, Federico Alberto Alfredo Felici, Alexander Karpushov, Joaquim Loizu Cisquella, Antoine Pierre Emmanuel Alexis Merle, Umar Sheikh, Xavier Llobet, Matteo Fontana, Simon Van Mulders, Alessandro Pau, Yanis Andrebe, Cristian Galperti, Joan Decker, Marcelo Baquero Ruiz, Cedric Kar-Wai Tsui, Mengdi Kong, Matteo Vallar, Olivier Claude Martin Février, Davide Galassi, Guang-Yu Sun, Pedro Andres Molina Cabrera, Filippo Bagnato, Roberto Maurizio, Oulfa Chellaï, Mirko Wensing, Claudia Colandrea, Curdin Tobias Wüthrich, Sophie Danielle Angelica Gorno, Francesco Carpanese, Nicola Offeddu, Aylwin Iantchenko, Maurizio Giacomin, Lorenzo Martinelli, Oleg Krutkin, Dahye Choi, Federico Pesamosca, Hugo Antoine Georges Arnichand, Dmytry Mykytchuk, Benjamin Alexandre Vincent, Umesh Kumar, Arsène Stéphane Tema Biwole, Lorenzo Stipani, Anna Ngoc Minh Trang Vu, Jean Arthur Cazabonne, Stefano Marchioni, Miguel Filipe Silva Füglister, Renat Karimov, Ajay Chandrarajan Jayalekshmi

The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its c ...

IOP Publishing Ltd2022

Quantitative study of the trapped particle bunching instability in Langmuir waves

Stephan Brunner

The bunching instability of particles trapped in Langmuir waves is studied using Vlasov simulations. A measure of particle bunching is defined and used to extract the growth rate from numerical simulations, which are compared with theory [Dodin et al., Phy ...

Amer Inst Physics2015

Venus plus delta f: A bootstrap current calculation module for 3-D configurations

Wilfred Anthony Cooper, Stephan Brunner, Trach-Minh Tran

A new three-dimensional code, VENUS+delta f, for neoclassical transport calculations in nonaxisymmetric toroidal systems is presented. Numerical drift orbits from the original VENUS code and the delta f method developed for tokamak transport calculations a ...

2006

System size scaling of triangularity effects on global temperature gradient-driven gyrokinetic simulations

Laurent Villard, Stephan Brunner, Moahan Murugappan, Giovanni Di Giannatale

In this work, we explore the triangularity effects on turbulent transport employing global gyrokinetic simulations performed with the ORB5 code. Numerous experiments on the Tokamak á Configuration Variable (TCV) and, more recently, on the DIII-D machine, h ...

2024

Linear scattering theory of short-pulse reflectometry

Stefano Coda, Stephan Brunner, Oleg Krutkin

The linear scattering theory of short pulse reflectometry is presented. An expression for the scattering signal is obtained by applying the perturbation theory approach for solving the Helmholtz equation. Based on these analytical results, a method for mea ...

2023

Moment approach of the multi-species non-linear Coulomb collision operator adapted to particle-in-cell codes

Laurent Villard, Stephan Brunner, Emmanuel Lanti, Noé Thomas Elie Ohana, Claudio Gheller, Moahan Murugappan

In this article an approximated version of the multi-species, non-linear Coulomb collision operator is derived via the use of a truncated moment expansion of the distribution function to compute the Rosenbluth potentials. The evolution of the distribution ...

2021

A bucket sort algorithm for the particle-in-cell method on manycore architectures

Laurent Villard, Stephan Brunner, Trach-Minh Tran, Claudio Gheller

The Particle-In-Cell (PIC) method is effectively used in many scientific simulation codes. In order to optimize the performance of the PIC approach, data locality is required. This relies on efficient sorting algorithms. We present a bucket sort algorithm ...

Springer2016

Demonstrating the saturation of stimulated Brillouin scattering by ion acoustic decay using fully kinetic simulations

Stephan Brunner

The saturation of stimulated Brillouin scattering (SBS) by the decay to turbulence of the ion acoustic wave (IAW) that participates in the three-wave SBS interaction is demonstrated using a quasinoiseless one-dimensional numerical solution to the Vlasov-Ma ...

Amer Inst Physics2015

Global simulations of tokamak microturbulence: finite beta effects and collisions

Laurent Villard, Stephan Brunner, Trach-Minh Tran, Alberto Bottino, Sébastien Jolliet, Ben McMillan, Thibaut Vernay

In this paper, we present global nonlinear gyrokinetic simulations including finite beta effects and collisions in tokamak geometry. Global electromagnetic simulations using conventional delta-f particle in cell methods are very demanding, with respect to ...

Institute of Physics2011

Recent TCV results – innovative plasma shaping to improve plasma properties and insight

Olivier Sauter, Stefano Coda, Laurent Villard, Basil Duval, Timothy Goodman, Antoine Pochelon, Holger Reimerdes, Jean-Marc Moret, Stephan Brunner, Benoît Labit, Laurie Porte, Alberto Bottino, Alexander Karpushov, Sébastien Jolliet, Paolo Angelino, Alessandro Marinoni, Dávid Wágner, Jonathan Rossel, David Nicholas Wagner, Andreas Pitzschke

2012

A method for density fluctuation measurements using pulse reflectometry

Stefano Coda, Stephan Brunner, Oleg Krutkin

An analytical 1D model based on the WKB approximation is used to study the properties of a short pulse reflectometry diagnostic in a magnetic fusion device. Expressions linking the pulse delay with the parameters of the turbulence near the cut-off layer ar ...

IOP Publishing Ltd2023