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Laurent Villard

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Related publications (137)

Page 3 of 7

Nonlinear gyrokinetic PIC simulations in stellarators with the code EUTERPE

Laurent Villard, Eduardo Sanchez, Alberto Bottino

In this work, the first nonlinear particle-in-cell simulations carried out in a stellarator with the global gyrokinetic code EUTERPE using adiabatic electrons and realistic plasma parameters are reported. Several studies are conducted with the aim of enabl ...

Cambridge University Press2020

Linear multispecies gyrokinetic flux tube benchmarks in shaped tokamak plasmas

Olivier Sauter, Laurent Villard, Stephan Brunner, Yann Camenen, Emiliano Fable, Gabriele Merlo, Alice Burckel

Verification is the fundamental step that any turbulence simulation code has to be submitted in order to assess the proper implementation of the underlying equations. We have carried out a cross comparison of three flux tube gyrokinetic codes, GENE [F. Jen ...

2016

Towards the optimization of a gyrokinetic Particle-In-Cell (PIC) code on large-scale hybrid architectures

Laurent Villard, Stephan Brunner, Emmanuel Lanti, Trach-Minh Tran, Noé Thomas Elie Ohana, Claudio Gheller

With the aim of enabling state-of-the-art gyrokinetic PIC codes to benefit from the performance of recent multithreaded devices, we developed an application from a platform called the "PIC-engine" [1, 2, 3] embedding simplified basic features of the PIC me ...

2016

Finite beta effects on short wavelength ion temperature gradient modes

Laurent Villard

The electromagnetic effect is studied on the short wavelength branch of the ion temperature gradient mode in the linear regime for the first time using a global gyrokinetic model. The short wavelength ion temperature gradient mode growth rate is found to b ...

2020

Mode excitation by an antenna in global gyrokinetic simulations

Laurent Villard, Stephan Brunner, Emmanuel Lanti, Alberto Bottino, Ben McMillan, Noé Thomas Elie Ohana

In order to get a better understanding of the linear and non-linear plasma interaction of microinstabilities and associated turbulence with different specific modes, an antenna is implemented in the global gyrokinetic code ORB5. It consists in applying an ...

2018

Nonlinear dynamics of energetic-particle driven geodesic acoustic modes in ASDEX Upgrade

Laurent Villard, Alberto Bottino, Emmanuel Lanti, Noé Thomas Elie Ohana

Turbulence in tokamaks generates radially sheared zonal flows. Their oscillatory counterparts, geodesic acoustic modes (GAMs), appear due to the action of the magnetic field curvature. The GAMs can be driven unstable by an anisotropic energetic particle (E ...

AMER INST PHYSICS2020

A spectral global gyrokinetic approach to plasma linear microinstability analysis

Laurent Villard, Alberto Bottino, Paolo Angelino, Gloria Luisa Falchetto

With the term microinstabilities, we indicate a class of plasma drift waves such as the ion temperature gradient (ITG) mode, the trapped electron mode (TEM), and the electromagnetic Alfvenic ion temperature gradient (AITG) mode. They are usually driven by ...

2005

Experimental and numerical investigations of electron transport enhancement by electron-cyclotron plasma-wave interaction in tokamaks

Stefano Coda, Laurent Villard, Laurie Porte, Joan Decker, Aylwin Iantchenko, Jean Arthur Cazabonne, Giovanni Di Giannatale

Energy transfer from electron-cyclotron (EC) waves to the plasma is being routinely used in tokamaks to heat and drive current through the electron channel. Technical applications such as magnetohydrodynamic mode mitigation require power deposition with a ...

IOP Publishing Ltd2023

Collisional effects on positive and negative triangularity through local and global temperature gradient-driven and flux-driven gyrokinetic simulations

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

In this work, we explore the effects of collisions on turbulent transport, focusing on two different TCV magnetic equilibria featuring positive and negative triangularity. The investigation is conducted using gyrokinetic modeling. Both gradient-driven and ...

2025

Gyrokinetic simulations on many- and multi-core architectures with the global electromagnetic Particle-In-Cell Code ORB5

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

Gyrokinetic codes in plasma physics need outstanding computational resources to solve increasingly complex problems, requiring the effective exploitation of cutting-edge HPC architectures. This paper focuses on the enabling of ORB5, a state-of-the-art, fir ...

2021

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

Accuracy of momentum and gyrodensity transport in global gyrokinetic particle-in-cell simulations

Laurent Villard, Ben McMillan

Gyrokinetic Particle-In-Cell (PIC) simulations based on conservative Lagrangian formalisms admit transport equations for conserved quantities such as gyrodensity and toroidal momentum, and these can be derived for arbitrary wavelength, even though previous ...

Amer Inst Physics2014

Numerics and computation in gyrokinetic simulations of electromagnetic turbulence with global particle-in-cell codes

Laurent Villard, Alberto Bottino, Emmanuel Lanti

Electromagnetic turbulence is addressed in tokamak and stellarator plasmas with the global gyrokinetic particle-in-cell codes ORB5 (E Lanti et al, Comp. Phys. Comm., 251, 107072 (2020)) and EUTERPE (V Kornilov et al, Phys. Plasmas, 11, 3196 (2004)). The la ...

2021

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 particle-in-cell simulations of electromagnetic turbulence in the presence of fast particles and global modes

Laurent Villard, Emmanuel Lanti

Global simulations of electromagnetic turbulence in circular-flux-surface tokamak and ASDEX-Upgrade geometry, tearing instabilities and their combination with the electromagnetic turbulence, nonlinear Alfvenic modes in the presence of fast particles and th ...

2022

A model for self-consistent simulation of ICRH suitable for integrating modelling

Laurent Villard

A self-consistent modelling of ion cyclotron resonance heating (ICRH) is reviewed with the aim of obtaining a fast robust scheme suitable for routine simulation for transport codes and data analysis. Due to the complexity of calculating the wave field and ...

IOP Publishing Ltd2013

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

A drift-kinetic Semi-Lagrangian 4D code for ion turbulence simulation

Olivier Sauter, Laurent Villard

A new code is presented here, named Gyrokinetic SEmi-LAgragian (GYSELA) code, which solves 4D drift-kinetic equations for ion temperature gradient driven turbulence in a cylinder (r, theta, z). The code validation is performed with the slab ITG mode that o ...

Elsevier2006

A full-wave solver of the Maxwell's equations in 3D cold plasmas

Laurent Villard, Wilfred Anthony Cooper, Pavel Popovitch

A new solver for Maxwell's equations in three-dimensional (3D) plasma configurations is presented. The new code LEMan (Low-frequency ElectroMagnetic wave propagation) determines a global solution of the wave equation in a realistic stellarator geometry at ...

2006