Personne

Wilfred Anthony Cooper

Publications associées (163)

Current and pressure gradient triggering and nonlinear saturation of low-n edge harmonic oscillations in tokamaks

Jonathan Graves, Wilfred Anthony Cooper, Antoine Pierre Emmanuel Alexis Merle, Daniele Brunetti, Andreas Kleiner

Non-axisymmetric free-boundary equilibrium computations are shown to represent nonlinearly saturated external kink modes and external kink-like sidebands coupled to pressure-driven infernal modes. In this study of edge harmonic oscillations associated with ...

IOP PUBLISHING LTD2019

Benchmark of gyrokinetic, kinetic MHD and gyrofluid codes for the linear calculation of fast particle driven TAE dynamics

Wilfred Anthony Cooper, Alberto Bottino

Fast particles in fusion plasmas may drive Alfven modes unstable leading to fluctuations of the internal electromagnetic fields and potential loss of particles. Such instabilities can have an impact on the performance and the wall-load of machines with bur ...

2018

Analytic study on low-n external ideal infernal modes in tokamaks with large edge pressure gradients

Jonathan Graves, Wilfred Anthony Cooper, Daniele Brunetti, Alberto Mariani

The problem of pressure driven infernal type perturbations near the plasma edge is addressed analytically for a circular limited tokamak configuration which presents an edge flattened safety factor. The plasma is separated from a metallic wall, either idea ...

2018

Analytic stability criteria for edge MHD oscillations in high performance ELM free tokamak regimes

Jonathan Graves, Wilfred Anthony Cooper, Daniele Brunetti, Alberto Mariani

A new dispersion relation, and associated stability criteria, is derived for low-n external kink and infernal modes, and is applied to modelling the stability properties of quiescent H-mode like regimes. The analysis, performed in toroidal geometry with la ...

IAEA2018

Stellarator nonlinearly saturated periodicity-breaking ideal magnetohydrodynamic equilibrium states

Jonathan Graves, Wilfred Anthony Cooper, Jonathan Marc Philippe Faustin, Hamish William Patten, Samuel Lanthaler, Madhusudan Raghunathan, Andreas Kleiner

The relaxation of the constraint of periodicity imposed by the external confining magnetic field coils in a nominally 4-field period Helias Advanced Stellarator configuration produces weak periodicity-breaking deformations of the plasma. The corrugations a ...

2018

Heavy Impurity Confinement in Hybrid Operation Scenario Plasmas with a Rotating 1/1 Continuous Mode

Jonathan Graves, Wilfred Anthony Cooper, David Pfefferlé, Madhusudan Raghunathan

In future tokamaks like ITER with tungsten walls, it is imperative to control tungsten accumulation in the core of operational plasmas, especially since tungsten accumulation can lead to radiative collapse and disruption. We investigate the behaviour of tu ...

IOP Science2017

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

Overview of the RFX-mod fusion science activity

Yi Zhang, Wilfred Anthony Cooper, Federico Alberto Alfredo Felici, Nicola Vianello, Matteo Vallar, Leonardo Pigatto, Elena Gaio, Alberto Ferro

This paper reports the main recent results of the RFX-mod fusion science activity. The RFX-mod device is characterized by a unique flexibility in terms of accessible magnetic configurations. Axisymmetric and helically shaped reversed-field pinch equilibria ...

Iop Publishing Ltd2017

Higher order Larmor radius corrections to guiding-centre equations and application to fast ion equilibrium distributions

Jonathan Graves, Wilfred Anthony Cooper, David Pfefferlé, Samuel Lanthaler

An improved set of guiding-centre equations, expanded to one order higher in Larmor radius than usually written for guiding-centre codes, are derived for curvilinear flux coordinates and implemented into the orbit following code VENUS-LEVIS. Aside from gre ...

Iop Publishing Ltd2017

Simulation of bootstrap current in 2D and 3D ideal magnetic fields in tokamaks

Olivier Sauter, Jonathan Graves, Wilfred Anthony Cooper, Madhusudan Raghunathan, Michael Pedro

We aim to simulate the bootstrap current for a MAST-like spherical tokamak using two approaches for magnetic equilibria including externally caused 3D effects such as resonant magnetic perturbations (RMPs), the effect of toroidal ripple, and intrinsic 3D e ...

Iop Publishing Ltd2016

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