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2009
Experiments have been performed on MAST using both external (n=1,2) and internal (n=3) resonant magnetic perturbation coils. ELM suppression has not been achieved even though vacuum modelling shows that either set of coils can produce a region for which the Chirikov parameter is greater than 1 wider than that required to produce ELM suppression in …
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2009
Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks. Using the increased heating capabilities PNBI ≤ 3.8 MWH-mode at Ip = 1.2 MA was accessed showing that the energy confinement on MAST scales more weakly with Ip and more strong…
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2009
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2009
One of the main operational aims of the MAST experiment [1] and the proposed MAST upgrade is to investigate possible mechanisms to control the q-profile and drive off-axis current. Experiments were carried out to determine the extent to which the q-profile may be modified using two different approaches, transient and steady-state. Transient effects…
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2008
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2007
Collective fast ion effects on flows in tokamaks are investigated analytically and numerically. A general analysis of noncollisional electrodynamic momentum transfer from fast ions to bulk plasma is presented, with polarization effects and dissipation in the bulk plasma taken into account. The analysis is illustrated using idealized simulations of …
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2006
The injection of neutral particle beams counter to the plasma current direction in the Mega-Ampere Spherical Tokamak (MAST) [A. Sykes, R. J. Akers, L. C. Appel and et al. , Nucl. Fusion, 41 , 1423 (2001)] leads to substantial losses of energetic beam ions and also rapid toroidal rotation. The electrodynamic consequences of energetic ion loss on tok…
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2005
It is well known that when neutral beams inject ions into trapped orbits in a tokamak, the transfer of momentum between the beam and the plasma occurs through the torque exerted by a radial return current. It is shown that this implies that the angular momentum transferred to the plasma can be larger than the angular momentum of the beam, if the in…
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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
The collisional interaction between neutral-beam ions and bulk plasma electrons leads to convective transport of particles and energy similar to the well-known Ware pinch. These transport fluxes are calculated, and it is found that the particle flux is outward when the neutral beams are in the same direction as the plasma current and inward otherwi…
Showing 31 - 40 of 57 UKAEA Paper Results