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2012
Lower hybrid current drive (LHCD) with modest powers ( 10% of the total power input) has been used for the first time to completely stabilize performance limiting neoclassical tearing modes in many COMPASS-D tokamak discharges. The stabilizing effect in these experiments is consistent with a reduction in the free energy available in the current pro…
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2012
Two possible ways of modifying the linear tearing mode index, by active magnetic feedback and by drift kinetic effects of deeply trapped particles, are analytically investigated. Magnetic feedback schemes, studied in this work, are found generally stabilizing for Δ′. The drift kinetic effects from both thermal particles and hot ions tend to redu…
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2012
Two methods for calculating tearing mode stability are described in this paper. A fast method using the recently improved T7 code (Ham et al. 2012 Plasma Phys. Control. Fusion 54 025009) and a new method based on the MARS-F MHD stability code (Liu et al. 2000 Phys. Plasmas 7 3681) which constructs the tearing mode solution from calculated basis fun…
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2012
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2011
Data from forced Vertical Displacement Event (VDE) experiments in the Mega Ampere Spherical Tokamak (MAST) indicate that the plasma is highly destabilised above z displacements of 0.4m. Previous work investigating the plasma response to vertical plasma perturbations in MAST had found it to be more non-linear than an equivalent conventionally-shaped…
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2011
It is well known that stabilization of the resistive wall mode (RWM) may allow fusion power to be significantly increased for a given magnetic field in advanced tokamak operation. The principle of stabilization of the RWM by rotation has been established both experimentally and theoretically. Recent experimental results have indicated stabilization…
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2011
Stabilization of the resitive wall mode (RWM) may allow fusion power to be doubled for a given magnetic field in advanced tokamak operation. Experimental evidence from DIII-D and other machines suggests that plasma rotation can stabilize the RWM. Several authors (Finn 1995 Phys. Plasmas 2 3782, Bondeson Xie 1997 Phys. Plasmas 4 2081) have construct…
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2011
Derek Robinson was a leading UK plasma physicist of his generation. After an early success in measuring the electron temperature in the ZETA plasma through the Thomson scattering of laser light, he became a key member of the team from Culham Laboratory sent to Moscow in 1968 to verify the high temperatures claimed by the Russians for their T3 tokam…
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2010
Multiple resonances in the edge-localized mode (ELM) frequency (f ELM ) as a function of the edge safety factor q 95 have been observed for the first time with an applied low n (1/41; 2) field on the JET tokamak. Without an n 1/4 1 field applied, f ELM increases slightly from 20 to 30 Hz by varying the q 95 from 4 to 5 in a type-I ELMy H-mode plasm…
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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…
Showing 31 - 40 of 74 UKAEA Paper Results