Concept

Amortissement Landau

Publications associées (24)

A model of non-Maxwellian electron distribution function for the analysis of ECE data in JET discharges

Mikhail Maslov, Javier García Hernández, Samuele Mazzi

Recent experiments performed in JET at high level of plasma heating, in preparation of, and during the DT campaign have shown significant discrepancies between electron temperature measurements by Thomson Scattering (TS) and Electron Cyclotron Emission (EC ...

E D P SCIENCES2023

Linear and nonlinear excitation of TAE modes by external electromagnetic perturbations using ORB5

Laurent Villard, Emmanuel Lanti, Alberto Bottino, Mohsen Sadr

The excitation of toroidicity-induced Alfven eigenmodes (TAEs) using prescribed external electromagnetic perturbations (hereafter 'antenna') acting on a confined toroidal plasma, as well as its nonlinear couplings to other modes in the system, is studied. ...

IOP Publishing Ltd2022

ICRF modelling in 2D and 3D magnetic configurations using a hot plasma model

Wilfred Anthony Cooper, Jonathan Graves, Mike Machielsen

The generation of energetic trapped ions is important for experiments investigating their confinement in 3D magnetic fields, for plasma heating, for studies into unwanted drive of instabilities, and improved transport regimes. An effective way to generate ...

2021

Effect of the tangential NBI current drive on the stability of pressure and energetic particle driven MHD modes in LHD plasma

Wilfred Anthony Cooper, Joao Varela

The aim of the present study is to analyze the stability of the pressure gradient driven modes (PM) and Alfven eigenmodes (AE) in the large helical device (LHD) plasma if the rotational transform profile is modified by the current drive of the tangential n ...

IOP Publishing Ltd2020

Modeling of TAE mode excitation with an antenna in realistic X-point geometry

Ambrogio Fasoli, Duccio Testa

Experimentally, it is observed that Toroidal Alfven Eigenmodes (TAEs) are difficult to excite with an external antenna when the plasma is in X-point geometry. Here, the effect of the X-point geometry on the efficiency of the TAE excitation with the externa ...

AMER INST PHYSICS2020

Linear theory of electron-plasma waves at arbitrary collisionality

Paolo Ricci, Stephan Brunner, 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

Long-lived coupled peeling ballooning modes preceding ELMs on JET

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia, Alessandro Pau, Pierre-Thomas Paul Brun, Cristian Sommariva, Henri Weisen, Richard Pitts, Sun Hee Kim, Yann Camenen, Jan Horacek, Javier García Hernández, Marco Wischmeier, Mikhail Maslov, Nicola Vianello, Miguel Fernández Ruiz, Federico Nespoli, Antonio José Pereira de Figueiredo, Liang Yao, Yao Zhou, David Pfefferlé, Dalziel Joseph Wilson, Robin Humphry-Baker, Davide Galassi, José Pedro Rebelo Ferreira Marques, Ana Francisca Leal Silva Soares, Jonathan Marc Philippe Faustin, Daniel Scott Alessi, Arnout Lodewijk M Beckers, Julio Rodriguez, Hamish William Patten, Jonnathan Cesar Hidalgo Acosta, Samuel Lanthaler, Li Shuai, Pedro Camilo de Oliveira e Silva, Alberto Hernando de Castro, Vlad Trifa, Bernhard Sieglin, Rebecca Hill, Partha Dutta, Otto Asunta

In some JET discharges, type-I edge localised modes (ELMs) are preceded by a class of low-frequency oscillations (Perez et al 2004 Nucl. Fusion 44 609). While in many cases the ELM is triggered during the growth phase of this oscillation, it is also observ ...

IOP Publishing Ltd2019

Scaling of the geodesic acoustic mode amplitude on JET

This work aims at establishing the parameter space for the existence of geodesic acoustic modes (GAMs) on JET as well as investigating their driving and damping mechanisms predicted by different theoretical models. This was achieved using an experimental d ...

2018

Radial localization of edge modes in Alcator C-Mod pedestals using optical diagnostics

Christian Gabriel Theiler

Dedicated experiments in ion cyclotron range heated enhanced D-alpha (EDA) H-mode and I-mode plasmas have been performed on Alcator C-Mod to identify the location of edge fluctuations inside the pedestal and to determine their plasma frame phase velocity. ...

Institute of Physics2017

Vlasov simulations of electron-ion collision effects on damping of electron plasma waves

Stephan Brunner, Trach-Minh Tran

Collisional effects can play an essential role in the dynamics of plasma waves by setting a minimum damping rate and by interfering with wave-particle resonances. Kinetic simulations of the effects of electron-ion pitch angle scattering on Electron Plasma ...

Amer Inst Physics2016

Kinetic simulations and reduced modeling of longitudinal sideband instabilities in non-linear electron plasma waves

Stephan Brunner, Loïc Hausammann

Kinetic Vlasov simulations of one-dimensional finite amplitude Electron Plasma Waves are performed in a multi-wavelength long system. A systematic study of the most unstable linear sideband mode, in particular its growth rate gamma and quasi- wavenumber de ...

Amer Inst Physics2014

Electron and ion kinetic effects on non-linearly driven electron plasma and ion acoustic waves

Stephan Brunner

Fully non-linear kinetic simulations of electron plasma and ion acoustic waves (IAWs) have been carried out with a new multi-species, parallelized Vlasov code. The numerical implementation of the Vlasov model and the methods used to compute the wave freque ...

Amer Inst Physics2013

Analysis of damping rate measurements of toroidal Alfven eigenmodes as a function of n: part I

Ambrogio Fasoli, Duccio Testa, Theodoros Panis

Complementing the database approach that has been presented in part I, this paper probes into individual plasma discharges and investigates the damping rate variations that are driven by the evolving plasma configurations. In addition to confirming the sta ...

IOP Publishing Ltd2012

Two-dimensional Vlasov simulation of electron plasma wave trapping, wavefront bowing, self-focusing, and sideloss

Stephan Brunner

Two-dimensional Vlasov simulations of nonlinear electron plasma waves are presented, in which the interplay of linear and nonlinear kinetic effects is evident. The plasma wave is created with an external traveling wave potential with a transverse envelope ...

American Institute of Physics (AIP)2011

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

Pedestal Characteristics and MHD Stability of H-Mode Plasmas in TCV

Andreas Pitzschke

The tokamak à configuration variable (TCV) is unique in its ability to create a variety of plasma shapes and to heat the electron population in high density regimes using microwave power at the third harmonic of the electron cyclotron frequency. In the fra ...

EPFL2011

Single speed solutions of the Vlasov-Poisson equations for Coulombian and Newtonian systems in nD

Philippe Choquard

Results of theoretical and numerical investigations concerning the space-time evolution in nD of Coulombian systems known in Plasma Physics and Newtonian systems known in Cosmology are reported here. A generic, canonical Hamiltonian formulation is given (1 ...

2008

Diagnostic Techniques for Measuring Suprathermal Electron Dynamics in Plasmas

Stefano Coda

Plasmas, both in the laboratory and in space, are often not in thermodynamic equilibrium, and the plasma electron distribution function is accordingly non-Maxwellian. Suprathermal electron tails can be generated by external drives, such as rf waves and ele ...

American Institute of Physics2008

Time resolved measurements by the pulse height analysis soft x-ray diagnostic on TCV

Basil Duval

A single chord, single processing chain, hybrid (analog/digital) pulse height analysis diagnostic has been developed for the TCV tokamak, aiming to provide the evolution of the plasma electron temperature with a software selectable minimum temporal resolut ...

2007

Energetic particle physics studies on Alcator C-Mod

Ambrogio Fasoli, Yu Lin

Energetic particle physics is studied in Alcator C-Mod in reactor relevant regimes with high density and equilibrated electron and ion temperatures. Stable Alfven eigenmodes are excited with low-power active magnetohydrodynamic antennas in the absence of a ...

2007