UKAEA Journals

Showing 1 - 9 of 9 Journals Results
2016
CCFE-PR(16)25

The high-frequency noise measured by magnetic sensors, at levels above the typical frequency of resistive wall modes, is analyzed across a range of present tokamak devices including DIII-D, JET, MAST, ASDEX Upgrade, JT-60U, and NSTX. A high-pass filter enables identification of the noise component with Gaussian-like statistics that shares certain c…

Preprint Purchase
2014

A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle spac…

Published
2013

The kinetic effect of trapped energetic particles (EPs), arising from perpendicular neutral beam injection, on the stable low-n peeling modes in tokamak plasmas is investigated, through numerical solution of the mode’s dispersion relation derived from an energy principle. A resistive-wall peeling mode with m/n = 6/1, with m and n being the poloid…

Published
2011

An energetic-particle (EP)-driven “off-axis-fishbone-like mode (OFM)” often triggers a resistive wall mode (RWM) in JT-60U and DIII-D devices, preventing long-duration high-b N discharges. In these experiments, the EPs are energetic ions (70–85 keV) injected by neutral beams to produce high-pressure plasmas. EP-driven bursting events reduce t…

Published
2010

Two issues of the resistive wall mode (RWM) control code maturity are addressed: the inclusion of advanced mode damping physics beyond the ideal MHD description, and the possibility of taking into account the influence of 3D features of the conducting structures on the mode stability and control. Examples of formulations and computational results a…

Published
2010

The stability and resonant field response of current driven resistive wall modes are numerically studied for DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] low pressure plasmas. The resonant field response of the feedback-stabilized resistive wall mode is investigated both analytically and numerically, and compared with the response from intrin…

Published
2009

Self-consistent computations are carried out to study the stability of the resistive wall mode RWM in DIII-D J. L. Luxon, Nucl. Fusion 42 , 614 2002 plasmas with slow plasma rotation, using the hybrid kinetic-magnetohydrodynamic code MARS-K [Y. Q. Liu and et al. , Phys. Plasmas 15 , 112503 (2008)]. Based on kinetic resonances between the mode and t…

Published
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