R. V. Perez W. U. Boeglin D. S. Darrow M. Cecconello I. Klimek S. Y. Allan R. J. Akers D. L. Keeling K. G. McClements R. Scannell M. Turnyanskiy A. Angulo P. Avila O. Leon C. Lopez O. M. Jones N. J. Conway C. A. Michael
The proton detector (PD) measures 3 MeV proton yield distributions from deuterium-deuterium fusion reactions within the Mega Amp Spherical Tokamak (MAST). The PD’s compact four-channel system of collimated and individually oriented silicon detectors probes different regions of the plasma, detecting protons (with gyro radii large enough to be unco…
PublishedI.T. Chapman J.T. Holgate N. Ben Ayed G. Cunningham C.J. Ham J.R. Harrison A. Kirk G. Mcardle A. Patel R. Scannell The Mast Team
When resonant magnetic perturbations are applied in MAST, the plasma edge boundary experiences a three dimensional distortion, which can be a few percent of the minor radius in amplitude, in good agreement with ideal 3d equilibrium modelling. This displacement occurs in plasmas both with radial position feedback control applied, and without feedbac…
PublishedI.T. Chapman A. Kirk R.J. Akers C.J. Ham J.R. Harrison J. Hawke Y.Q. Liu K.G. McClements S. Pamela S. Saarelma R. Scannell A.J. Thornton The Mast Team
ELM mitigation has been demonstrated in MAST using resonant magnetic perturbations (RMPs) with toroidal mode number, n RM P = 2, 3, 4, 6. It has been observed that the mitigated ELM frequency increases with the amplitude of the applied field provided it is above a critical threshold. This threshold value depends on the mode number of the RMP, with …
PublishedJ.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,…
PublishedL. Garzotti J. Figueiredo C. M. Roach M. Valovic D. Dickinson G. Naylor M. Romanelli R. Scannell G. Szepesi The Mast Team
Reactor grade plasmas are likely to be fuelled by pellet injection. This technique transiently perturbs the profiles, driving the density profile hollow and flattening the edge temperature profile. After the pellet perturbation, the density and temperature profiles relax towards their quasi-steady-state shape. Microinstabilities influence plasma co…
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…
PublishedJ. Hawke R. Scannell M. Maslov J. B. Migozzi JET-EFDA Contributors
This work isolated the cause of the observed discrepancy between the electron temperature (Te) measurements before and after the JET Core LIDAR Thomson Scattering (TS) diagnostic was upgraded. In the upgrade process, stray light filters positioned just before the detectors were removed from the system. Modelling showed that the shift imposed on the…
PublishedJ. Hawke R. Scannell J. Harrison R. Huxford P. Bohm
The super-X divertor on MAST Upgrade will be diagnosed by a Thomson scattering diagnostic. A preliminary design of the collection optics and calculations of the diagnostic’s performance are discussed in this paper. As part of the design the location and size of the collection cell were optimized to minimize vignetting, especially in the region of…
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…
Published