I. T. Chapman A. Kirk C. J. Ham J. R. Harrison Y. Q. Liu et al.
Type-I Edge Localised Modes (ELMs) have been mitigated in MAST through the application of n = 3, 4, and 6 resonant magnetic perturbations. For each toroidal mode number of the non-axisymmetric applied fields, the frequency of the ELMs has been increased significantly, and the peak heat flux on the divertor plates reduced commensurately. This increa…
PublishedA. Kirk I.T. Chapman J. Harrison Yueqiang Liu E. Nardon S. Saarelma R. Scannell A.J. Thornton The Mast Team
The application of resonant magnetic perturbations (RMPs) with a toroidal mode number of n=4 or n=6 to lower single null plasmas in the MAST tokamak produces up to a factor of 5 increase in Edge Localized Mode (ELM) frequency and reduction in plasma energy loss associated with type-I ELMs. A threshold current for ELM mitigation is observed above wh…
PublishedI.T. Chapman A. Kirk S. Saarelma J.R. Harrison R. Scannell The Mast Team
The application of resonant magnetic perturbations with toroidal mode number n = 4 or n = 6 is observed to result in a significant increase in ELM frequency, despite a reduction in the edge pressure gradient. A picture for how type-I ELMs are mitigated, or destabilised, when magnetic perturbations are applied is proposed. Despite the magnetic pertu…
PublishedI.T. Chapman W.A. Cooper A. Kirk C.J. Ham J.R. Harrison A. Patel S.D. Pinches R. Scannell A.J. Thornton The Mast Team
The distortion of the plasma boundary when three-dimensional resonant magnetic perturbations are applied has been measured in MAST H-mode plasmas. When the n = 3 resonant magnetic perturbations are applied to control edge localised modes, the plasma experiences a strong toroidal corrugation. The displacement of the plasma boundary is measured at va…
PublishedA. Kirk J. Harrison Yueqiang Liu E. Nardon I. T. Chapman P. Denner The Mast Team
The application of nonaxisymmetric resonant magnetic perturbations (RMPs) with a toroidal mode number n . 6 in the MAST tokamak produces a significant reduction in plasma energy loss associated with type-I edge localized modes (ELMs), the first such observation with n>3 . During the ELM mitigated stage clear lobe structures are observed in visible-…
PublishedM Valovic L Garzotti C Gurl R Akers J Harrison C Michael G Naylor R Scannell The Mast Team
Access into H-mode is studied in the MAST tokamak when plasma is fuelled by cryogenic pellets. It is shown that pellet fuelling from the high field side allows access to Hmode in plasmas heated by neutral beams. Simple and two-stage L-H transitions are identified. The results of comparison of the L-H transitions with pellet injection with transitio…
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