J.C. Hillesheim F.I. Parra,M. Barnes N.A. Crocker H. Meyer W.A. Peebles R. Scannell A. Thornton The Mast Team
Tokamak plasmas rotate even without any external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and H-mode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model,…
PublishedA. Kirk Yueqiang Liu I.T. Chapman J. Harrison E. Nardon R. Scannell A.J. Thornton The Mast Team
The application of resonant magnetic perturbations (RMPs) with a toroidal mode number of n=3 to connected double null plasmas in the MAST tokamak produces up to a factor of 9 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 which…
PublishedF. Orain M. Bécoulet G. Dif-Pradalier G. Huijsmans S. Pamela E. Nardon C. Passeron G. Latu V. Grandgirard A. Fil A. Ratnani I. Chapman A. Kirk A. Thornton M. Hoelzl P. Cahyna
The interaction of static Resonant Magnetic Perturbations (RMPs) with the plasma flows is modeled in toroidal geometry, using the non-linear resistive MHD code JOREK, which includes the X-point and the scrape-off-layer. Two-fluid diamagnetic effects, the neoclassical poloidal friction and a source of toroidal rotation are introduced in the model to…
PublishedA. Kirk I.T. Chapman T.E. Evans C. Ham J.R. Harrison G. Huijsmans Y. Liang Y.Q. Liu A. Loarte W. Suttrop A.J. Thornton
All current estimations of the energy released by type I ELMs indicate that, in order to ensure an adequate lifetime of the divertor targets on ITER, a mechanism is required to decrease the amount of energy released by an ELM, or to eliminate ELMs altogether. One such amelioration mechanism relies on perturbing the magnetic field in the edge plasma…
PublishedA.Kirk I.T. Chapman Yueqiang Liu P. Cahyna P. Denner G. Fishpool C.J. Ham J.R. Harrison Yunfeng Liang E. Nardon S. Saarelma R. Scannell A.J. Thornton The Mast Team
Sustained ELM mitigation has been achieved using RMPs with a toroidal mode number of n=4 and n=6 in lower single null and with n=3 in connected double null plasmas on MAST. The ELM frequency increases by up to a factor of eight with a similar reduction in ELM energy loss. A threshold current for ELM mitigation is observed above which the ELM freque…
PublishedS. Elmore S. Y. Allan A. Kirk A. J. Thornton J. R. Harrison P. Tamain M. Kocan J. W. Bradley The Mast Team
Knowledge of the ion temperature (Ti) is of key importance for determining heat fluxes to the divertor and plasma facing components, however data regarding this is limited compared to electron temperature (Te) data. Ti measurements at the divertor target, between edge-localised modes (inter-ELM) H-mode, have been made using a novel retarding field …
PublishedA.J. Thornton A. Kirk I.T. Chapman J.R. Harrison The Mast Team
Edge localised modes (ELMs) are a concern for future devices as they can limit the operational lifetime of the divertor. The mitigation of ELMs can be performed by the application of resonant magnetic perturbations (RMPs) which act to degrade the pressure gradient in the edge of the plasma. Investigations of the effect of RMPs on MAST have been per…
PublishedA.J. Thornton K.J. Gibson J.R. Harrison M. Lehnen R. Martin A. Kirk The Mast Team
Disruptions are of significant concern to future devices, due to the large amount of energy released during the rapid quenching of the plasma. Disruption mitigation has been performed on MAST, to study the effect on heat loads and disruption time scales in a spherical tokamak. Massive gas injection is performed using a disruption mitigation valve c…
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 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…
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