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1996
This paper reports on the ideal magnetohydrodynamic (MHD) stability of tokamak field profiles that have a non-monotonic safety factor q ( r ). An analytic criterion is obtained for these ‘‘inverse shear’’ profiles by expanding in inverse aspect ratio and assuming that the minimum in q is slightly less than the m / n value of the mode under …
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1992
The experimental performance of a high-brightness neutral-beam system is described which has been designed and manufactured by Culham Laboratory under contract to the Princeton Plasma Physics Laboratory. The neutral beam serves as a diagnostic on the PBX-M experiment and is used to perform studies of high-bet a, bean-shaped, neutral-beam-heated pla…
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1991
The purpose of this paper is to investigate the possible relationships between transport properties such as thermal diffusivity and resistivity on the one hand, and the magnetic properties such as q profile and toroidal flux change on the other, in tokamaks that exist under macroscopically quasistationary conditions. It is experimentally well estab…
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1991
This is Part II of a study of resonant perturbations, such as resistive tearing and ballooning modes, in a torus. These are described by marginal ideal magnetohydrodynamic (MHD) equations in the regions between resonant surfaces; matching across these surfaces provides the dispersion relation. Part I [Phys. Fluids B3, 1532 (1991)] described how all…
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1989
Particle beams have been developed at the Culham Laboratory for many years, mainly for application to the production of high-temperature plasmas. These developments included demonstration offundamental plasma physics such as particle trapping, heating, and current drive coupled to continuous advances in the physics and technology of ion beam produc…
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1989
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1989
When a suitable accelerating voltage is applied to extract negative ions from a volume production source, electrons are also extracted. If no means of suppression is utilized, the electron current in a hydrogen plasma would typically be of the order of 80-100 times the negative-ion current. In the accelerator designs in use at Culham Laboratory, el…
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1989
Magnetic feedback control has been used in the DITE tokamak to substantially reduce saturated m = 2, n = 1 instabilities in both Ohmic discharges and discharges with lower-hybrid current drive (LHCD). Feedback has been used for the first time to significantly increase the disruptive density limit in a tokamak. LHCD on DITE stabilizes the sawtooth i…
Showing 431 - 438 of 438 UKAEA Paper Results