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Stephan Brunner

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Publications associées (134)

Orb5: A global electromagnetic gyrokinetic code using the PIC approach in toroidal geometry

Stephan Brunner, Laurent Villard, Alberto Bottino, Sébastien Jolliet, Paolo Angelino, Thibaut Vernay, Ben McMillan, Emmanuel Lanti, Julien Stanislas Pierre Dominski, Noé Thomas Elie Ohana, Aaron Lewis Scheinberg, Claudio Gheller

This paper presents the current state of the global gyrokinetic code Orb5 as an update of the previous reference (Jolliet et al., 2007). The Orb5 code solves the electromagnetic Vlasov–Maxwell system of equations using a PIC scheme and also includes collis ...

2019

Global turbulence features across marginality and non-local pedestal-core interactions

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

Spatially non-local aspects of turbulent transport in tokamak plasmas are examined with global gyrokinetic simulations using the ORB5 code. Inspired by very accurate measurements in the TCV tokamak in L-mode, we initialise plasma profiles with constant log ...

2019

Investigation of the role of electron temperature gradient modes in electron heat transport in TCV plasmas

Stephan Brunner, Olivier Sauter, Alexander Karpushov, Laurie Porte, Claudio Marini, Alberto Mariani

Electron-scale micro-turbulence driven by the electron temperature gradient (ETG) instability has recently been shown to impact the electron heat transport in tokamaks. Given the relevance of these mechanisms for ITER scenarios, a new study has been carrie ...

IOP Publishing Ltd2019

First principles gyrokinetic analysis of electromagnetic plasma instabilities

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

A two-fold analysis of electromagnetic core tokamak instabilities in the framework of the gyrokinetic theory is presented. First principle theoretical foundations of the gyrokinetic theory are used to explain and justify the numerical results obtained with ...

2019

Gyrokinetic analysis of radial dependence and global effects on the zero particle flux condition in a TCV plasma

Stephan Brunner, Olivier Sauter, Gabriele Merlo, Alberto Mariani

In small-sized tokamaks, finite Larmor radius effects could lead to a significant discrepancy between gyrokinetic local flux-tube results and global ones. This has been highlighted by previous turbulent transport studies as in McMillan et al (2010 Phys. Re ...

IOP2019

The effect of background flow shear on gyrokinetic turbulence in the cold ion limit

Stephan Brunner, Ben McMillan, Justin Richard Ball

2019

High-Order Accurate Conservative Finite Difference Methods For Vlasov Equations In 2D+2V

Stephan Brunner

This manuscript discusses discretization of the Vlasov-Poisson system in 2D+2V phase space using high-order accurate conservative finite difference algorithms. One challenge confronting direct kinetic simulation is the significant computational cost associ ...

SIAM PUBLICATIONS2019

Pullback Scheme Implementation in ORB5

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

The pullback scheme is implemented in the global gyrokinetic particle-in-cell code ORB5 (Jolliet et al., 2007[1]) to mitigate the cancellation problem in electromagnetic simulations. The equations and the discretisation used by the code are described. Nume ...

Elsevier2019

Linearized Coulomb Collision Operator for Simulation of Interpenetrating Plasma Streams

Stephan Brunner

We present an extension of a linearized Coulomb collision operator, previously used in several Eulerian kinetic codes for like-species collisions and unlike-species collisions in the case where the backgrounds about which the linearization is made all are ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Linear theory of electron-plasma waves at arbitrary collisionality

Stephan Brunner, Paolo Ricci, Rogério Manuel Cabete De Jesus Jorge, Vyacheslav Konovets, Sonia Gamba

The dynamics of electron-plasma waves is described at arbitrary collisionality by considering the full Coulomb collision operator. The description is based on a Hermite–Laguerre decomposition of the velocity dependence of the electron distribution function ...

Cambridge University Press2019

Effects of collisionality and T e /T i on fluctuations in positive and negative δ tokamak plasmas

Stephan Brunner, Ambrogio Fasoli, Olivier Sauter, Stefano Coda, Laurie Porte, Gabriele Merlo, Matteo Fontana, Ajay Chandrarajan Jayalekshmi

The effects of negative triangularity () on confinement and fluctuations in plasmas covering a large range of parameters were investigated on the tokamak à configuration variable (TCV). The conditions explored in this paper include discharges where neutral ...

IOP Publishing Ltd2019

Mode excitation by an antenna in global gyrokinetic simulations

Stephan Brunner, Laurent Villard, Alberto Bottino, Ben McMillan, Emmanuel Lanti, 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

Experimental observations of modes with geodesic acoustic character from the core to the edge in the TCV tokamak

Stephan Brunner, Laurent Villard, Stefano Coda, Benoît Labit, Christian Gabriel Theiler, Zhouji Huang, Gabriele Merlo

2018

Identifying microturbulence regimes in a TCV discharge making use of physical constraints on particle and heat fluxes

Stephan Brunner, Olivier Sauter, Julien Stanislas Pierre Dominski, Gabriele Merlo, Antoine Pierre Emmanuel Alexis Merle, Alberto Mariani

American Institute of Physics (AIP)2018

Investigating the radial structure of axisymmetric fluctuations in the TCV tokamak with local and global gyrokinetic GENE simulations

Stephan Brunner, Laurent Villard, Stefano Coda, Laurie Porte, Julien Stanislas Pierre Dominski, Gabriele Merlo, Matteo Fontana

2018

Gradient- and flux-driven global gyrokinetic simulations of ITG and TEM turbulence with an improved hybrid kinetic electron model

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

2018

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

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

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

An arbitrary wavelength solver for global gyrokinetic simulations. Application to the study of fine radial structures on microturbulence due to non-adiabatic passing electron dynamics

Stephan Brunner, Trach-Minh Tran, Laurent Villard, Ben McMillan, Julien Stanislas Pierre Dominski, Gabriele Merlo

The influence of the fine layers of the non-adiabatic passing electron response on electrostatic turbulent transport, previously studied systematically in flux tube geometry [Dominski et al., Phys. Plasmas 22, 062303 (2015)], is pursued in global geometry ...

Amer Inst Physics2017

Collisional damping rates for electron plasma waves reassessed

Stephan Brunner, Trach-Minh Tran

Collisional damping of electron plasma waves, the primary damping for high phase velocity waves, is proportional to the electron-ion collision rate, nu(ei,th). Here, it is shown that the damping rate normalized to nu(ei,th) depends on the charge state, Z, ...

Amer Physical Soc2017

Longitudinal and Transverse Instability of Ion Acoustic Waves

Stephan Brunner

Ion acoustic waves are found to be susceptible to at least two distinct decay processes. Which process dominates depends on the parameters. In the cases examined, the decay channel where daughter modes propagate parallel to the mother mode is found to domi ...

Amer Physical Soc2017

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