Concept

Coronal seismology

Publications associées (34)

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Modelling of Alfven waves in JET plasmas with the CASTOR-K code

Ambrogio Fasoli, Duccio Testa

A hybrid magnetohydrodynamic (M H D)-gyro-kinetic model CASTOR-K developed for the study of Alfven eigenmode (AE) stability in the presence of energetic ions has been applied to the interpretation of recent measurements of Alfven waves in JET. These includ ...

2002

MHD stability limits in the TCV tokamak

Holger Reimerdes

Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak à Configuration Variable (TCV), unique for its capability to produce a variety of poloidal plasma shapes, has been used to analyse ...

EPFL2001

Gyrokinetic modelling of macro-instabilities in high performance tokamak plasmas

Ambrogio Fasoli, Laurent Villard, Duccio Testa

The modelling of Alfvenic instabilities is discussed from the point of view of mode-conversion, showing how the development of the theory affects the predictions as the limitations of the models are gradually relaxed. Conventional tokamak plasmas are relat ...

2001

Prediction of Alfven eigenmode dampings in the Joint European Torus

Ambrogio Fasoli

Predictions from a gyrokinetic toroidal plasma model reproduce for the first time the evolution of Alfven eigenmode (AE) dampings over a range of discharges. The coupling between shear-and kinetic-Alfven waves is responsible for the main source of damping ...

1998

Measurement of the effective plasma ion mass in large tokamaks using global Alfven eigenmodes

Laurent Villard, Jonathan Bryan Lister

There is not yet a straightforward method for determining the D-T ratio in the centre of a tokamak plasma. One of the simpler measurements put forward in the past is the interpretation of the MHD spectrum in the frequency range of the global Alfven eigenmo ...

1998

The spectrum of n = 0 Alfven modes is calculated analytically and numerically in cylindrical and toroidal geometries. It includes global Alfven eigenmodes (GAEs) and surface modes (SMs) of the fast magnetoacoustic wave. These modes are not induced by toroi ...

1997

Determination of local tokamak parameters by magnetohydrodynamic spectroscopy

Ambrogio Fasoli

The influence of local equilibrium parameters on the Alfven spectrum is studied. The aim is to solve the inverse problem: identification of the plasma profiles, and especially the safety factor profile, using measurements of magnetohydrodynamic (MHD) waves ...

1997

Kinetic Alfvén eigenmodes in a hot tokamak plasma

Ambrogio Fasoli, Laurent Villard, Jonathan Bryan Lister, Kurt Appert

Global Alfven eigenmodes are studied using fluid and kinetic plasma models to determine how the finite Larmor excursions of the bulk species and the resonant Landau interactions modify the spectrum in the toroidicity Alfven eigenmode (TAE) range of frequen ...

IAEA1997

Alfven wave heating and stability

Laurent Villard, Stephan Brunner

Alfven waves in fusion plasmas play an important role in a number of situations. First, in Alfven Wave Heating (AWH) schemes. Second, both theory and experiment have demonstrated the existence of Global Alfven Eigenmodes (GAEs). GAEs have been observed in ...

1995

An Experimental-Study of the Harmonics Generated During Alfven-Wave Heating at Tca

Yves Martin, Jonathan Bryan Lister

During plasma excitation by high power Alfven waves at TCA, signals at harmonics of the generator frequency are observed in the plasma scrape-off layer. In this paper, experimental investigations of the sheath effect and the excitation efficiency and dispe ...

1993