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

Exploration of the parameter space for the excitation and saturation of Edge Harmonic Oscillations

This thesis presents advancements in the understanding of the plasma conditions leading to the excitation and saturation of the Edge Harmonic Oscillations (EHOs) observed during QH-mode operation in tokamak plasmas. Such operations represent a safer altern ...

EPFL2023

On the relationship between the multi-region relaxed variational principle and resistive inner-layer theory

Joaquim Loizu Cisquella, Ankit Kumar

We show that the variational energy principle of the multi-region relaxed magnetohydrodynamic (MRxMHD) model can be used to predict finite-pressure linear tearing instabilities. In this model, the plasma volume is sliced into sub-volumes separated by 'idea ...

2023

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 ...

Cambridge University Press2018

Equilibrium reconstruction in an iron core tokamak using a deterministic magnetisation model

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Martinus Gijs, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

In many tokamaks ferromagnetic material, usually referred to as an iron-core, is present in order to improve the magnetic coupling between the solenoid and the plasma. The presence of the iron core in proximity to the plasma changes the magnetic topology w ...

2018

Direct Measurements of the Damping of Alfvén Eigenmodes for an Assessment of their Stability Limits in Tokamak Plasmas

Theodoros Panis

Direct damping rate measurements of AEs are obtained using the active MHD spectroscopy system installed on the JET tokamak. The system was recently equipped with new antennas, designed to study especially the modes of intermediate toroidal mode number n, | ...

EPFL2010

Active excitation and damping rate measurement of intermediate-n Toroidal Alfvén Eigenmodes in JET, C-Mod and MAST plasmas

Ambrogio Fasoli, Duccio Testa, Theodoros Panis

The stability properties of Alfvén Eigenmodes (AEs) are investigated directly using external antenna excitation and detection of stable modes in a variety of plasma configurations in different devices. Dedicated methods to measure the AE damping rate separ ...

2010

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

Importance of centrifugal effects for the internal kink mode stability in toroidally rotating tokamak plasmas

Jonathan Graves

Analytical theory and two different magnetohydrodynamical stability codes are used in a study of the effects of toroidal plasma rotation on the stability of the ideal, internal kink mode in tokamaks. The focus of the paper is on the role that the centrifug ...

American Institute of Physics (AIP)2009

Edge kink/ballooning mode stability in tokamaks with separatrix

Olivier Sauter, Yves Martin, Laurent Villard, Andrei Martynov

Stability limits against external kink modes driven by large current density and pressure gradient values in the pedestal region are investigated for tokamak plasmas with separatrix. Stability diagrams for modes with different toroidal wave numbers under v ...

Institute of Physics2006

Kink instability of flux ropes anchored at one end and free at the other

Ivo Furno

The kink instability of a magnetized plasma column (flux rope) is a fundamental process observed in laboratory and in natural plasmas. Previous theoretical, experimental, and observational work has focused either on the case of periodic (infinite) ropes (r ...

2006