UKAEA Journals

Showing 21 - 30 of 30 Journals Results
2006

Active control of the resistive wall mode RWM for DIII-D [Luxon and Davis, Fusion Technol. 8 , 441 (1985)] plasmas is studied using the MARS-F code [Y. Q. Liu, and et al. , Phys. Plasmas 7 , 3681 (2000)]. Control optimization shows that the mode can be stabilized up to the ideal wall beta limit, using the internal control coils I-coils and poloidal…

Published
2006

Dedicated experiments in the DIII-D tokamak J. L. Luxon, Nucl. Fusion, 42 , 614 2002, the Joint European Torus JET P. H. Rebut, R. J. Bickerton, and B. E. Keen, Nucl. Fusion 25 , 1011 1985, and the National Spherical Torus Experiment NSTX M. Ono, S. M. Kaye, Y.-K. M. Peng et al. , Nucl. Fusion 40 , 557 2000 reveal the commonalities of resistive wal…

Published
2006

Reversed shear Alfvén eigenmodes RSAE that were observed in the Joint European Torus (JET) [P. H. Rebut and B. E. Keen, Fusion Technol. 11 , 13 (1987)] and DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] are studied with the ideal magnetohydrodynamic code NOVA-K C. [Z. Cheng, Phys. Rep. 211 , 1 (1992)]. It was found that the frequency behavior …

Published
2006

The ability to predict the stability of fast-particle-driven Alfvén eigenmodes in burning fusion plasmas requires a detailed understanding of the dissipative mechanisms that damp these modes. In order to address this question, the linear gyro-kinetic, electromagnetic code L IGKA [1] is employed to investigate their behaviour in realistic tokamak g…

Published
2005

Two fluid turbulence models, the drift wave based quasilinear 1.5D Weiland model and the electromagnetic global 3D nonlinear model CUTIE , have been used to account for heat pinch evidence in off-axis modulated electron cyclotron heating experiments in the Rijnhuizen Tokamak Project. Both models reproduce the main features indicating inward heat co…

Published
2004

A microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time re…

Published
2003

Particle transport in magnetized plasmas is investigated with a fluid model of drift wave turbulence. An analytical calculation shows that magnetic field curvature and thermodiffusion drive an anomalous pinch. The curvature driven pinch velocity is consistent with the prediction of turbulence equipartition theory. The thermodiffusion flux is found …

Published
2003

Plasma configurations with shear reversal are prone to the excitation of unusual Alfven eigenmodes by energetic particles. These modes exhibit a quasiperiodic pattern of predominantly upward frequency sweeping ( Alfven cascades ) as the safety factor q changes in time. This work presents a theory that employs two complementary mechanisms for establ…

Published
2001

Alfvén spectra in a reversed-shear tokamak plasma with a population of energetic ions exhibit a quasiperiodic pattern of primarily upward frequency sweeping (Alfvén cascade). Presented here is an explanation for such asymmetric sweeping behavior which involves finding a new energetic particle mode localized around the point of zero magnetic shear…

Published
2000

Relaxation is the result of turbulence in a plasma that behaves essentially as an ideal conducting fluid, but has a small resistivity and viscosity. These small effects are locally enhanced by the turbulence and lead to reconnection of magnetic field lines. This destroys an infinity of topological constraints, leaving only the total magnetic helici…

Published