Concept

Accélérateur MHD

Publications associées (107)

MHD stability limits in the TCV tokamak

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

Configuration flexibility and extended regimes in Large Helical Device

Wilfred Anthony Cooper, Kenji Tanaka

Recent experimental results in the Large Helical Device have indicated that a large pressure gradient can be formed beyond the stability criterion for the Mercier (high-n) mode. While the stability against an interchange mode is violated in the inward-shif ...

2001

Fast magnetic fluctuation diagnostics for Alfven eigenmode and magnetohydrodynamics studies at the Joint European Torus

Ambrogio Fasoli, Jean-Marc Moret

Alfven eigenmodes and other magnetohydrodynamic phenomena have been studied in tokamak plasmas at the Joint European Torus (JET) using a new eight-channel, 4 s, 1 MHz, 12-bit data acquisition system (KC1F) in conjunction with the JET fast Mirnov magnetic f ...

2000

Model for humpback relaxation oscillations

Olivier Sauter, Timothy Goodman, Ivo Furno, Holger Reimerdes, Antoine Pochelon, Roland Behn

An interpretation of non-standard, central MHD events in the TCV tokamak during localized ECRH is presented. It is shown that the non-standard behaviour is a consequence of specific features in the electron temperature profile produced when ECRH power is d ...

2000

Effect of triangular and elongated plasma shape on the sawtooth stability

Olivier Sauter, Timothy Goodman, Holger Reimerdes, Antoine Pochelon, Andrei Martynov

In the TCV tokamak the sawtooth period and the sawtooth amplitude are observed to depend strongly on the shape of the poloidal plasma cross section. Systematic scans of plasma elongation and triangularity show small sawteeth with short periods at high elon ...

2000

Experimental and theoretical stability limits of highly elongated tokamak plasmas

Olivier Sauter, Ivo Furno, Holger Reimerdes, Antoine Pochelon

Stability limits of highly elongated, D-shaped plasmas have been measured in the TCV (tokamak a configuration variable) tokamak. It is found that the plasma current is limited by kink-type disruptions, preceded by magnetohydrodynamic (MHD) mode activity. T ...

1998

Energy principles for linear dissipative systems with application to resistive MHD stability

A formalism for the construction of energy principles for dissipative systems is presented. It is shown that dissipative systems satisfy a conservation law for the bilinear Hamiltonian provided the Lagrangian is time invariant. The energy on the other hand ...

1997

Normal curvature, local magnetic shear and parallel current density in tokamaks and torsatrons

Wilfred Anthony Cooper

Reversed magnetic shear is associated with large negative surface averaged parallel current densities that increase in magnitude towards the plasma edge and guarantee stability at large beta in tokamaks. The surface averaged parallel current density is sma ...

1997

Beta limits in long-pulse tokamak discharges

Olivier Sauter, Hartmut Zohm

The maximum normalized beta achieved in long-pulse tokamak discharges at low collisionality falls significantly below both that observed in short pulse discharges and that predicted by the ideal MHD theory. Recent long-pulse experiments, in particular thos ...

1997

Resistive interchange modes in negative central shear tokamaks with peaked pressure profiles

Olivier Sauter

Resistive interchange modes can be driven unstable by large pressure gradients in the negative central magnetic shear (NCS) region of advanced tokamaks. Localized stability analysis reveals that the resistive interchange stability criterion (D-R less than ...

1996

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