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Wilfred Anthony Cooper

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Publications associées (112)

Helical ITER hybrid scenario equilibria

Wilfred Anthony Cooper, Olivier Sauter, Jonathan Graves

Numerical computations of ITER equilibria in the hybrid scenario using a three-dimensional (3D) magnetohydrodynamic equilibrium code with nested magnetic flux surfaces demonstrate the formation of internal 3D helical cores similar to saturated ideal intern ...

IOP2011

MHD equilibrium and stability of tokamaks and RFP systems with 3D helical cores

Wilfred Anthony Cooper, Olivier Sauter, Jonathan Graves

Bifurcated magnetohydrodynamic (MHD) equilibrium states are computed for ITER hybrid scenario and RFX-mod SHAx configurations with very flat or reversed core magnetic shear conditions. In the ITER studies, the minimum inverse rotational transform qmin is n ...

IOP Publishing2011

Three-dimensional equilibria and transport in RFX-mod: A description using stellarator tools

Wilfred Anthony Cooper

RFX-mod self-organized single helical axis (SHAx) states provide a unique opportunity to advance 3D fusion physics and establish a common knowledge basis in a parameter region not covered by stellarators and tokamaks. The VMEC code has been adapted to the ...

American Institute of Physics (AIP)2011

Full-field drift Hamiltonian particle orbits in 3D geometry

Stephan Brunner, Wilfred Anthony Cooper, Jonathan Graves

A Hamiltonian/Lagrangian theory to describe guiding centre orbit drift motion which is canonical in the Boozer coordinate frame has been extended to include full electromagnetic perturbed fields in anisotropic pressure 3D equilibria with nested magnetic fl ...

IOP2011

Magnetohydrodynamic properties of nominally axisymmetric systems with 3D helical core

Wilfred Anthony Cooper, Olivier Sauter, Jonathan Graves

Magnetohydrodynamic equilibrium states with a three-dimensional helical core are computed to model the MAST spherical tokamak and the RFX-mod reversed field pinch. The boundary is fixed as axisymmetric. The MAST equilibrium state has the appearance of an i ...

2011

Integrated modelling of Ion Cyclotron Resonant Heating in toroidal system

Stephan Brunner, Wilfred Anthony Cooper, Nicolas Mellet, Martin Jucker, Jonathan Graves

An integrated model capable of self-consistent Ion Cyclotron Resonant Heating (ICRH) simulations has been developed. This model includes both full shaping and pressure effects, warm contributions to the dielectric tensor, pressure anisotropy and finite orb ...

Elsevier B.V2011

Overview of the RFX fusion science program

Wilfred Anthony Cooper, Elena Gaio, Nicola Vianello, Alberto Ferro, Zheng Wang

This paper summarizes the main achievements of the RFX fusion science program in the period between the 2008 and 2010 IAEA Fusion Energy Conferences. RFX-mod is the largest reversed field pinch in the world, equipped with a system of 192 coils for active c ...

IOP Publishing Ltd2011

Macroscopic Stability of High Beta MAST plasmas

Wilfred Anthony Cooper, Jonathan Graves

The high-beta capability of the spherical tokamak, coupled with a suite of world-leading diagnostics on MAST, has facilitated significant improvements in the understanding of performance-limiting core instabilities in high performance plasmas. For instance ...

IOP Publishing Ltd2011

Magentohydrodynamic Properties of Nominally Axisymmetric Systems with 3D Helical Core

Wilfred Anthony Cooper, Olivier Sauter, Jonathan Graves

IOP Publishing2011

Drift stabilization of ballooning modes in a high-$\langle \beta \rangle$ LHD configuration

Wilfred Anthony Cooper, Jonathan Graves, Lucie Brocher

Ideal MHD yields at best inconclusive predictions about the stability of the LHD heliotron for

\langle \beta \rangle \geq 3\%

. We investigate the impact of the drift stabilization of ballooning modes for the inward shifted LHD configuration (vacuum magne ...

IOP Publishing Ltd2010

Tokamak Magnetohydrodynamic Equilibrium States with Axisymmetric Boundary and a 3D Helical Core

Wilfred Anthony Cooper, Antoine Pochelon, Olivier Sauter, Laurent Villard, Jonathan Graves

Magnetohydrodynamic (MHD) equilibrium states with imposed axisymmetric boundary are computed in which a spontaneous bifurcation develops to produce an internal three-dimensional (3D) configuration with a helical structure in addition to the standard axisym ...

American Physical Society2010

Magnetic Reconnection Triggering Magnetohydrodynamic Instabilities during a Sawtooth Crash in a Tokamak Plasma

Wilfred Anthony Cooper, Jonathan Graves

Thomson scattering measurements with subcentimeter spatial resolution have been made during a sawtooth crash in a Mega Ampere Spherical Tokamak fusion plasma. The unparalleled resolution of the temperature profile has shed new light on the mechanisms that ...

APS2010

Drift stabilization of ballooning modes in an inward-Shifted LHD configuration

Wilfred Anthony Cooper, Jonathan Graves, Lucie Brocher

A drift-magnetohydrodynamic theory is applied to a background anisotropic pressure equilibrium state to generate a drift corrected ballooning mode equation. The ratio of the mode frequency to the hot particle drift frequency constitutes the critical expans ...

Wiley-VCH2010

Three-dimensional anisotropic pressure free boundary equilibria

Wilfred Anthony Cooper, Jonathan Graves

Free boundary three-dimensional anisotropic pressure magnetohydrodynamic equilibria with nested magnetic flux surfaces are computed through the minimisation of the plasma energy functional

W={\int}_{V}{d^3}x\left[{B^2}/(2\mu_0)+p_{||}/(\Gamma-1)\right]

. ...

2009

MHD Stability Analysis of IDB Plasma in LHD

Wilfred Anthony Cooper

The characteristics of magnetohydrodynamics (MHD) stability of plasmas with the internal diffusion barrier (IDB) are intensively studied in the Large Helical Device (LHD) experiment. These plasma are produced by the rapid fueling into the core region with ...

The Japan Society of Plasma Science and Nuclear Fusion Research2009

BECOOL: Ballooning eigensolver with COOL finite elements

Wilfred Anthony Cooper, Jonathan Graves

An incompressible variational ideal ballooning mode equation is discretized with the COOL finite element discretization scheme using basis functions composed of variable order Legendre polynomials. This reduces the second order ordinary differential equati ...

2009

Bootstrap current calculations with the SPBSC and the VENUS delta f codes for the Large Helical Device

Wilfred Anthony Cooper, Olivier Sauter, Trach-Minh Tran

Total bootstrap current calculations with the updated VENUS+δf code that incorporates energy convolution and the momentum correction technique have been performed for the reference tokamak JT-60U cases and for the experimental Large Helical Device (LH ...

IOP Publishing Ltd2009

A geometry interface for gyrokinetic microturbulence investigations in toroidal configurations

Wilfred Anthony Cooper

The GENE/GIST code package is developed for the investigation of plasma microturbulence, suitable for both stellarator and tokamak configurations. The geometry module is able to process typical equilibrium files and create the interface for the gyrokinetic ...

American Institute of Physics (AIP)2009

Parallelization of the LEMan Code with MPI and OpenMP

Wilfred Anthony Cooper, Nicolas Mellet

The low-frequency wave propagation code LEMan has been parallelized. Due to large memory requirement but fast computation with the cold model, the parallelization is limited to a low number of processors. The specific block-tridiagonal structure of the mat ...

Springer-Verlag New York, Ms Ingrid Cunningham, 175 Fifth Ave, New York, Ny 10010 Usa2009

Moment approach to the bootstrap current in nonaxisymmetric toroidal plasmas using deltaf Monte Carlo methods

Wilfred Anthony Cooper, Trach-Minh Tran

To evaluate the bootstrap current in nonaxisymmetric toroidal plasmas quantitatively, a deltaf Monte Carlo method is incorporated into the moment approach. From the drift-kinetic equation with the pitch-angle scattering collision operator, the bootstrap cu ...

American Institute of Physics (AIP)2009

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