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2007
The destabilization of ideal magnetohydrodynamic ballooning modes at finite rotation shear is demonstrated for the model s - equilibrium by exploiting low magnetic shear, s , to simplify the two-dimensional stability problem to a one-dimensional eigenvalue problem. This simpler calculation captures the same features as exhibited by a full two-dimen…
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2006
Edge-localized modes (ELMs) are cyclic disturbances in the outer region of tokamak plasmas that are influential in determining present and future tokamak performance. In this Letter, we outline an approach to modeling ELMs in which we envisage toroidal peeling modes initiating a Taylor relaxation [Phys. Rev. Lett. 33 , 1139 (1974)] of a tokamak out…
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2006
A corrected relativistic collision operator is used to derive a Fokker-Planck equation for the distribution function of relativistic suprathermal electrons in a weakly relativistic plasma, which is then solved by a procedure similar to that employed in Connor and Hastie [Nucl. Fusion 15 , 415 (1975)]. Analytical expressions are derived for the elec…
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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…
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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…
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2006
Present day tokamaks are capable of generating toroidal flows approaching the ion sound speed. Such toroidal rotation is known to have a stabilising effect on resistive wall modes[1]. Here the effects of plasma rotation and diamagnetic drifts on the n = 1 internal kink mode and high n ballooning modes are presented with specific comparison to exper…
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2005
A full orbit code is used to compute collisionless losses of fusion particles from three proposed burning plasma tokamaks: the International Tokamak Experimental Reactor ITER; a spherical tokamak power plant (STPP) [T. C. Hender, A. Bond, J. Edwards, P. J. Karditsas, K. G. McClements, J. Mustoe, D. V. Sherwood, G. M. Voss, and H. R. Wilson, Fusion …
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2005
A set of external coils (A-coils) capable of producing nonaxisymmetric, predominantly n =1, fields with different toroidal phase and a range of poloidal mode m spectra has been used to determine the threshold amplitude for mode locking over a range of plasma parameters in Alcator C-Mod [I. H. Hutchinson, R. Boivin, F. Bombarda, P. Bonoli, S. Fairfa…
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2005
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2004
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated wi…
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