Jonathan Graves

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Related publications (326)

Understanding JET-C quiescent phases with edge harmonic magnetohydrodynamic activity and comparison with behaviour under ITER-like wall conditioning

Wilfred Anthony Cooper, Jonathan Graves, Daniele Brunetti, Alberto Mariani, Andreas Kleiner, Guillermo Bustos Ramirez

An analysis of edge localised mode-free (quiescent) H-mode discharges exhibiting edge harmonic magnetoydrodynamic activity in the JET-carbon wall machine is presented. It is observed that the otherwise quiescent pulses with multiple-n harmonic oscillations ...

IOP Publishing Ltd2022

Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Jieping Zhu, Jonathan Graves, Joaquim Loizu Cisquella, Eduardo Sanchez, Antoine Baillod, Mike Machielsen, Xiaoxue Han, Nicola Vianello, Jonathan Marc Philippe Faustin, Alberto Bottino

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been ...

IOP Publishing Ltd2022

Overview of the TCV tokamak experimental programme

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Timothy Goodman, Jonathan Graves, Yves Martin, Jean-Marc Moret, Stefano Alberti, Ivo Furno, Duccio Testa

The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its c ...

IOP Publishing Ltd2022

Verification and validation of linear gyrokinetic and kinetic-MHD simulations for internal kink instability in DIII-D tokamak

Jonathan Graves

Verification and linear validation of the internal kink instability in tokamak have been performed for both gyrokinetic (GTC) and kinetic-MHD codes (GAM-solver, M3D-C1-K, NOVA, XTOR-K). Using realistic magnetic geometry and plasma profiles from the same eq ...

IOP Publishing Ltd2022

Pressure driven long wavelength MHD instabilities in an axisymmetric toroidal resistive plasma

Jonathan Graves

A general set of equations that govern global resistive interchange, resistive internal kink and resistive infernal modes in a toroidal axisymmetric equilibrium are systematically derived in detail. Tractable equations are developed such that resistive eff ...

2022

Heavy impurity transport in tokamaks subject to plasma rotation, NTV and the influence of saturated ideal MHD perturbations

Jonathan Graves, Cristian Sommariva, Eduardo José Lascas Neto

Strongly peaked tungsten accumulation is a common feature of high performance plasma scenarios in JET with the ITER-like wall, particularly during MHD activity induced by m/n = 1/1 continuous modes. This study investigates the effect of 1/1 long living int ...

2022

Finite magnetic well effects on resistive and drift-resistive ballooning modes in a shaped tokamak

Jonathan Graves

The impact of plasma shaping through magnetic well modifications on the stability of resistive ballooning modes (RBMs) in tokamaks is analysed, also including finite diamagnetic flows. Various limiting cases of the dispersion relation, obtained by matching ...

IOP Publishing Ltd2022

Modeling of saturated external MHD instabilities in tokamaks: A comparison of 3D free boundary equilibria and nonlinear stability calculations

Jonathan Graves

3D free boundary equilibrium computations have recently been used to model external kinks and edge harmonic oscillations (EHOs), comparing with linear MHD stability codes, and nonlinear analytic theory [Kleiner et al., Phys. Plasma Controlled Fusion 61, 08 ...

2022

Stellarator optimization for nested magnetic surfaces at finite β and toroidal current

Jonathan Graves, Joaquim Loizu Cisquella, Antoine Baillod

Good magnetic surfaces, as opposed to magnetic islands and chaotic field lines, are generally desirable for stellarators. In previous work, Landreman et al. [Phys. of Plasmas 28, 092505 (2021)] showed that equilibria computed by the Stepped-Pressure Equili ...

American Institute of Physics (AIP)2022

Overview of JET results for optimising ITER operation

Olivier Sauter, Ambrogio Fasoli, Jonathan Graves, Duccio Testa, Patrick Blanchard, Alessandro Pau, Federico Alberto Alfredo Felici, Cristian Sommariva, Umar Sheikh, Henri Weisen

The JET 2019-2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully a ...

IOP Publishing Ltd2022

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