Publications by Jonathan Graves

Toroidal drift precession and wave-particle interaction in shaped tokamaks with finite beta and neoclassical equilibrium effects

The drift kinetic equation is analysed for linear instabilities that are sensitive to the toroidal drift motion of long-mean free path particle populations. The interaction Lagrangian is resolved, and the toroidal drift precession evaluated for realistic t ...

Iop Publishing Ltd2013

Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

Olivier Sauter, Stefano Coda, Timothy Goodman, Jonathan Graves, Costanza Zucca, Martin Jucker, Otto Asunta

13 MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neoclassical tearing modes (NTMs). However, since t ...

IOP2013

Fast seeding of NTMs by sawtooth crashes in TCV and their preemption using ECRH

Olivier Sauter, Basil Duval, Timothy Goodman, Jonathan Graves, Duccio Testa, Holger Reimerdes, Antoine Pochelon

Many tokamaks have observed that sawteeth of sufficient duration may trigger neoclassical tearing modes (NTMs) that lead to plasma performance degradation. In this paper, TCV's ability to accurately control the period of individual sawteeth is exploited, u ...

Iop Publishing Ltd2013

Integrated modelling of ICRH in a quasi-axisymmetric stellarator

Jonathan Graves, Wilfred Anthony Cooper, Martin Jucker

We apply the code package SCENIC to a two field-period quasi-axisymmetric stellarator. Ion cyclotron resonance heating (ICRH) is applied both on the high-and low-field side to a 1% He-3 minority in a deuterium plasma. It is shown that due to toroidal varia ...

2012

Assessment of turbulent beam ion redistribution in tokamaks through velocity space-dependent gyrokinetic analyses

Ambrogio Fasoli, Jonathan Graves, Wilfred Anthony Cooper, Stephan Brunner, Mattia Albergante

We present the interface between a gyrokinetic code and a guiding centre code dedicated to the study of fast ion turbulent transport. A set of velocity space-dependent (kinetic) transport quantities, representing the link between the two codes, is presente ...

Int Atomic Energy Agency2012

Bifurcated Helical Core Equilibrium States in Tokamaks

Olivier Sauter, Basil Duval, Stefano Coda, Jonathan Graves, Wilfred Anthony Cooper, Holger Reimerdes, Benoît Labit, Antoine Pochelon, David Pfefferlé, Federico David Halpern, Daniele Brunetti, Jonathan Rossel, Mattia Albergante

Tokamaks with weak to moderate reversed central shear in which the minimum rotational transform

q_{min}

is in the neighbourhood of unity can trigger bifurcated MagnetoHydrodynamic (MHD) equilibrium states, one of which is similar to a saturated ideal ...

2012

Exploitation of a general-coordinate guiding centre code for the redistribution of fast ions in deformed hybrid tokamak equilibria

Jonathan Graves, Wilfred Anthony Cooper, David Pfefferlé

Self-consistent fast ion distributions are usually obtained using a code that solves the guiding-centre equations, with an appropriate fast ion source (e.g. NBI pinis) and sink (e.g. collision operators). Straight field-line coordinate systems, such as Boo ...

Iop Publishing Ltd2012

Equilibrium and stability in a heliotron with anisotropic hot particle slowing-down distribution

Jonathan Graves, Wilfred Anthony Cooper

The equilibrium and linear fluid Magnetohydrodynamic (MHD) stability in an inward-shifted large helical device heliotron configuration are investigated with the 3D ANIMEC and TERPSICHORE codes, respectively. A modified slowing-down distribution function is ...

American Institute of Physics2012

MHD properties in the core of ITER-like hybrid scenarios

Jonathan Graves, Wilfred Anthony Cooper, Federico David Halpern, Daniele Brunetti

MHD stability is studied in the frame of ITER like hybrid scenarios, characterized by weak reversed shear, with particular attention on ideal internal kink modes and infernal mode stability. Numerical simulations for ITER like equilibria, with hollow q pro ...

Iop Publishing Ltd2012

Recent Advances in Sawtooth Control

Olivier Sauter, Stefano Coda, Jonathan Graves, James Paley

Important advances have been made recently in the invention and application of experimental methods to control the sawtooth instability in tokamak plasmas. The primary means of control involves the application of either ion cyclotron resonance heating (ICR ...

American Nuclear Society2011

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Toroidal drift precession and wave-particle interaction in shaped tokamaks with finite beta and neoclassical equilibrium effects

Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

Fast seeding of NTMs by sawtooth crashes in TCV and their preemption using ECRH

Integrated modelling of ICRH in a quasi-axisymmetric stellarator

Assessment of turbulent beam ion redistribution in tokamaks through velocity space-dependent gyrokinetic analyses

Bifurcated Helical Core Equilibrium States in Tokamaks

Exploitation of a general-coordinate guiding centre code for the redistribution of fast ions in deformed hybrid tokamak equilibria

Equilibrium and stability in a heliotron with anisotropic hot particle slowing-down distribution

MHD properties in the core of ITER-like hybrid scenarios

Recent Advances in Sawtooth Control

Toroidal drift precession and wave-particle interaction in shaped tokamaks with finite beta and neoclassical equilibrium effects

Bifurcated Helical Core Equilibrium States in Tokamaks

Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

Integrated modelling of ICRH in a quasi-axisymmetric stellarator

Fast seeding of NTMs by sawtooth crashes in TCV and their preemption using ECRH

Assessment of turbulent beam ion redistribution in tokamaks through velocity space-dependent gyrokinetic analyses

Exploitation of a general-coordinate guiding centre code for the redistribution of fast ions in deformed hybrid tokamak equilibria

Equilibrium and stability in a heliotron with anisotropic hot particle slowing-down distribution

MHD properties in the core of ITER-like hybrid scenarios

Recent Advances in Sawtooth Control