A. Kirk T. O’Gorman S. Saarelma R. Scannell H.R. Wilson The Mast Team
The H-mode pedestal characteristics on MAST are measured in a variety of Connected Double Null (CDN) and Single Null Divertor (SND) discharges. In CDN discharges the edge density pedestal width in spatial co-ordinates is similar on both the high and low field sides suggesting that the width may be determined by neutral penetration. However, in SND …
PublishedI. T. Chapman M. F. De Bock S. D. Pinches M. R. Turnyanskiy Mast Team V. G. Igochine M. Maraschek G. Tardini Asdex Upgrade Team
Sawtooth behavior has been investigated in plasmas heated with off-axis neutral beam injection in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44 , 569 (2003)] and the Mega-Ampere Spherical Tokamak MAST [A. Sykes and et al. , Nucl. Fusion 41 , 1423 (2001)]. Provided that the fast ions are well confined, the sawtooth period is foun…
PublishedA.Kirk E.Nardon R.Akers M.Bécouleta G.Detemmerman B.Dudsonb B.Hnatc Y.Q.Liu R.Martin P.Tamain D.Taylor The Mast Team
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 …
PublishedV.F.Shevchenko M.R.O’Brien D.Taylor Mast Team
Electron Bernstein wave (EBW) assisted plasma current start-up has been demonstrated for the first time in a tokamak. It was shown that plasma currents up to 17 kA can be generated non- inductively by 100 kW of RF power injected. With optimized vertical field ramps, plasma currents up to 33 kA have been achieved without the use of solenoid flux. It…
PublishedM-D Hua IT Chapman SD Pinches RJ Hastie The Mast Team
‘Advanced tokamak’ (AT) scenarios were developed with the aim of reaching tokamak steady-state operation. They are designed to optimise the self-generated current, whilst also reaching sufficiently high plasma pressure to achieve optimal fusion reaction rates. AT scenarios exhibit non-monotonic to flat safety factor profiles (q, a measure of th…
PublishedP. G. Carolan A. Patel N. J. Conway R. J. Akers C. A. Bunting G. F. Counsell J. Dowling M. R. Dunstan A. Kirk F. Lott M. N. Price M. R. Tournianski M. J. Walsh The Mast Team
The Mega Amp Spherical Torus ( MAST ) diagnostic needs are strongly influenced by physics goals that often require diagnostic integration and cross-mapping, especially in fine-scale investigations, such as transport barriers. Conversely, the unrivalled viewing access to the edge, scrape-off layer ( SOL ) and divertor regions, provided by the MAST o…
PublishedA. Kirk H. R.Wilson G. F. Counsell R. Akers E. Arends S. C. Cowley J. Dowling B. Lloyd M. Price M.Walsh Mast Team
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated wi…
PublishedGhassan Y. Antar Glenn Counsell Yang Yu Brian Labombard Pascal Devynck
The nature of intermittency, long observed in magnetic fusion devices, was revisited lately [G. Antar et al. , Phys. Rev. Lett. 87 , 065001 (2001)]. It was shown that intermittency is caused by large-scale events with high radial velocity reaching about 1/10th of the sound speed. These type of structures were named ‘‘avaloids.’’ In the pres…
Published