TY - JOUR
T1 - Overview of MAST results
JF - Nuclear Fusion
Y1 - 2015
A1 - Chapman, I.T.
A1 - Adamek, J.
A1 - Akers, R. J.
A1 - Allan, S.
A1 - Appel, L.
A1 - Asunta, O.
A1 - Barnes, M.
A1 - N. Ben Ayed
A1 - Hawke, J.
A1 - Bigelow, T.
A1 - Boeglin, W.
A1 - Bradley, J.
A1 - Brünner, J.
A1 - Cahyna, P.
A1 - Carr, M.
A1 - Caughman, J.
A1 - Cecconello, M.
A1 - Challis, C.
A1 - Chapman, S.
A1 - Chorley, J.
A1 - Colyer, G.
A1 - Conway, N.
A1 - Cooper, W. A.
A1 - Cox, M.
A1 - Crocker, N.
A1 - Crowley, B.
A1 - Cunningham, G.
A1 - Danilov, A.
A1 - Darrow, D.
A1 - Dendy, R.
A1 - Diallo, A.
A1 - Dickinson, D.
A1 - Diem, S.
A1 - Dorland, W.
A1 - Dudson, B.
A1 - Dunai, D.
A1 - Easy, L.
A1 - Elmore, S.
A1 - Field, A.
A1 - Fishpool, G.
A1 - Fox, M.
A1 - Fredrickson, E.
A1 - Freethy, S.
A1 - Garzotti, L.
A1 - Ghim, Y. C.
A1 - Gibson, K.
A1 - Graves, J.
A1 - Gurl, C.
A1 - Guttenfelder, W.
A1 - Ham, C.
A1 - Harrison, J.
A1 - Harting, D.
A1 - Havlickova, E.
A1 - Hawkes, N.
A1 - Hender, T.
A1 - Henderson, S.
A1 - Highcock, E.
A1 - Hillesheim, J.
A1 - Hnat, B.
A1 - Holgate, J.
A1 - Horacek, J.
A1 - Howard, J.
A1 - Huang, B.
A1 - Imada, K.
A1 - Jones, O.
A1 - S. Kaye
A1 - Keeling, D.
A1 - Kirk, A.
A1 - Klimek, I.
A1 - Kocan, M.
A1 - Leggate, H.
A1 - Lilley, M.
A1 - Lipschultz, B.
A1 - Lisgo, S.
A1 - Liu, Y. Q.
A1 - Lloyd, B.
A1 - Lomanowski, B.
A1 - Lupelli, I.
A1 - Maddison, G.
A1 - J. Mailloux
A1 - Martin, R.
A1 - McArdle, G.
A1 - McClements, K.
A1 - McMillan, B.
A1 - Meakins, A.
A1 - Meyer, H.
A1 - Michael, C.
A1 - Militello, F.
A1 - Milnes, J.
A1 - Morris, A. W.
A1 - Motojima, G.
A1 - Muir, D.
A1 - Nardon, E.
A1 - Naulin, V.
A1 - Naylor, G.
A1 - Nielsen, A.
A1 - O'Brien, M.
A1 - O'Gorman, T.
A1 - Ono, Y.
A1 - Oliver, H.
A1 - Pamela, S.
A1 - Pangioni, L.
A1 - Parra, F.
A1 - Patel, A.
A1 - Peebles, W.
A1 - Peng, M.
A1 - Perez, R.
A1 - Pinches, S.
A1 - Piron, L.
A1 - Podesta, M.
A1 - Price, M.
A1 - Reinke, M.
A1 - Ren, Y.
A1 - Roach, C.
A1 - Robinson, J.
A1 - Romanelli, M.
A1 - Rozhansky, V.
A1 - Saarelma, S.
A1 - Sangaroon, S.
A1 - Saveliev, A.
A1 - Scannell, R.
A1 - Schekochihin, A.
A1 - Sharapov, S.
A1 - Sharples, R.
A1 - Shevchenko, V.
A1 - Silburn, S.
A1 - J. Simpson
A1 - Storrs, J.
A1 - Takase, Y.
A1 - Tanabe, H.
A1 - Tanaka, H.
A1 - Taylor, D.
A1 - Taylor, G.
A1 - Thomas, D.
A1 - Thomas-Davies, N.
A1 - Thornton, A.
A1 - Turnyanskiy, M.
A1 - Valovic, M.
A1 - Vann, R.
A1 - Walkden, N.
A1 - Wilson, H.
A1 - Wyk, L. V.
A1 - Yamada, T.
A1 - Zoletnik, S.
A1 - MAST Team
A1 - MAST Upgrade Teams
VL - 55
IS - 10
U1 - FP
U2 - TP
U5 - 9d7b191e90422e8ed8bcf2078b75987f
ER -
TY - JOUR
T1 - Assessing the merits of resonant magnetic perturbations with different toroidal mode numbers for controlling edge localised modes
JF - Nuclear Fusion
Y1 - 2014
A1 - Chapman, I.T.
A1 - Kirk, A.
A1 - Akers, R. J.
A1 - Ham, C. J.
A1 - Harrison, J. R.
A1 - Hawke, J.
A1 - Liu, Y. Q.
A1 - McClements, K. G.
A1 - Pamela, S.
A1 - Saarelma, S.
A1 - Scannell, R.
A1 - Thornton, A. J.
A1 - MAST Team
AB - An increase in ELM frequency has been demonstrated in MAST by applying resonant magnetic perturbations (RMPs) with toroidal mode number, n RMP = 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 higher n RMP having a larger critical value. For the same ELM frequency, the reduction in the peak heat load on the divertor plates is approximately the same for all RMP configurations. The RMPs give rise to perturbations to the plasma shape, with lobe structures occurring due to the tangled magnetic fields near the X-point, and corrugations of the plasma boundary at the midplane. The X-point lobe length increases linearly with the applied field when above a threshold, with RMPs of higher toroidal mode number giving rise to longer lobes for the same applied resonant field. Similarly, the midplane displacements increase with the applied field strength, though the corrugation amplitude is less dependent upon the RMP configuration. For all n RMP , the RMPs result in enhanced particle transport and a reduction in the pedestal pressure gradient caused by an increased pedestal width, which is found to be consistent with a decrease in the critical pressure at which infinite- n ballooning modes are driven unstable in non-axisymmetric plasmas. The plasma rotation braking is strongest for lowest n RMP whilst the degradation of access to H-mode resultant from the application of RMPs are non-monotonic in n RMP , with the optimal case for both occurring for n RMP = 4. Whilst there are advantages and disadvantages for all RMP configurations, the configurations found to be optimised in terms of pedestal degradation, access to H-mode, plasma rotation and distortion to the plasma configuration in MAST are n RMP = 3 or 4, consistent with the configurations anticipated for use in ITER.
VL - 54
IS - 12
U1 - FP
U2 - PDG
U5 - 9480959b16b2e7d1de210b2ae74e6645
ER -
TY - JOUR
T1 - Correction of the spectral calibration of the Joint European Torus core light detecting and ranging Thomson scattering diagnostic using ray tracing
JF - Review of Scientific Instruments
Y1 - 2013
A1 - Hawke, J.
A1 - Scannell, R.
A1 - Maslov, M.
A1 - Migozzi, J. B.
AB - This work isolated the cause of the observed discrepancy between the electron temperature (T-e) 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 stray light filters transmission functions due to the variations in the incidence angles of the collected photons impacted plasma measurements. To correct for this identified source of error, correction factors were developed using ray tracing models for the calibration and operational states of the diagnostic. The application of these correction factors resulted in an increase in the observed T-e, resulting in the partial if not complete removal of the observed discrepancy in the measured T-e between the JET core LIDAR TS diagnostic, High Resolution Thomson Scattering, and the Electron Cyclotron Emission diagnostics.
VL - 84
SN - 0034-6748
UR - http://scitation.aip.org/content/aip/journal/rsi/84/10/10.1063/1.4824074
U1 - FP
U2 - PDG
U5 - 555e171cd6807457cf8359bf2d1c3b43
ER -
TY - JOUR
T1 - Outline of optical design and viewing geometry for divertor Thomson scattering on MAST upgrade
JF - Journal of Instrumentation
Y1 - 2013
A1 - Hawke, J.
A1 - Scannell, R.
A1 - Harrison, J.
A1 - Huxford, R.
A1 - Bohm, P.
AB - 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 interest close to the divertor strike point. The design process was complicated by the limited access available in the closed divertor geometry. In the study of the diagnostic's performance, the radial resolution, projection of the laser image onto the fiber bundle, and impact of depth of field with a multiple laser system were investigated. In this design there is a trade-off between the resolution of the system and the lifetime of the beam dump. For this reason the beam has its focal point at the start of the viewing region and diverges in width to approximately five millimeters near the divertor tile. The effect of this large variation in beam width is examined primarily at the two extremes by means of ray trace modeling. This model takes an object with dimensions of the beam width imaged onto the fiber bundle to investigate the effect of misalignment for a narrow or broad laser image. In a similar manner ray tracing was performed to determine the effects of depth of field for four and two laser systems. As the electron density of the system may be low, performance analysis considers firing multiple lasers simultaneously to improve photon statistics.

VL - 8
IS - 11
U1 - FP

U2 - PDG

U5 - bc432db4e4cd856d6e7b3a556b348d42
ER -