J. Beal A. Widdowson K. Heinola A. Baron-Wiechec K.J. Gibson J.P. Coad E. Alves B. Lipschultz A. Kirschner H.G. Esser G.F. Matthews S. Brezinsek JET Contributors
Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used t…
Preprint PublishedB. Colling T. Eade M.J. Joyce R. Pampin F. Seyvet A. Turner V. Udintsev
Shutdown dose rate calculations have been performed on an integrated ITER C-lite neutronics model with equatorial port 10. A fully shielded configuration, optimized for a given diagnostic designs (i.e. shielding in all available space within the port plug drawers), results in a shutdown dose rate in the port interspace, from the activation of mater…
Preprint PublishedM. J. Leyland M. N. A. Beurskens J. C. Flanagan L. Frassinetti K. J. Gibson M. Kempenaars M. Maslov R. Scannell JET Contributors
The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Local…
Preprint PublishedL. Easy F. Militello J. Omotani N. R. Walkden B. Dudson
The propagation of filaments in the Scrape Off Layer (SOL) of tokamaks largely determines the plasma profiles in the region. In a conduction limited SOL, parallel temperature gradients are expected, such that the resistance to parallel currents is greater at the target than further upstream. Since the perpendicular motion of an isolated filament is…
Preprint PublishedY. Tsui E. Surrey D. Hampshire
Demountable superconducting magnet coils would offer signi fi cant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave…
PublishedA. Xu D.E.J. Armstrong C. Beck M. P. Moody G. D.W. Smith P. A. J. Bagot S. G. Roberts
In tungsten plasma-facing fusion reactor components, Ta is the third most abundant element formed by transmutation (after Re and Os), yet little is known about the behaviour of W-Ta alloys under irradiation and any effects Ta might have on Re clustering in W-Re-Ta alloys. In this study, W-4.5 at.%Ta, W-2 at.% Re-1 at.%Ta andW-2 at.%Re alloys were e…
PublishedH. Tanabe T. Yamada T. Watanabe K. Gi M. Inomoto R. Imazawa M. Gryaznevich C. Michael B. Crowley N. J. Conway R. Scannell J. Harrison I. Fitzgerald A. Meakins N. Hawkes K. G. McClements T. O'Gorman C. Z. Cheng Y. Ono The MAST team
In the last three years, magnetic reconnection research in the MAST spherical tokamak achieved major progress by use of new 32 chord ion Doppler tomography, 130 channel YAG and 300 channel Ruby Thomson scattering diagnostics. In addition to the previously achieved high power plasma heating during merging, detailed full temperature profile measureme…
Preprint PublishedP.M.S. Buller I. Pusztai S.L. Newton J.T. Omotani
In tokamak transport barriers, the radial scale of profile variations can be comparable to a typical ion orbit width, which makes the coupling of the distribution function across flux surfaces important in the collisional dynamics. We use the radially global steady-state neoclassical f code Perfect to calculate poloidal and toroidal flows, and radi…
Preprint PublishedB. Layden Z. S. Qu M. Fitzgerald M. J. Hole
A number of tools have recently been developed to study equilibrium and stability in tokamaks with pressure anisotropy. Here we apply these tools to a Mega Ampere Spherical Tokamak (MAST) discharge to calculate equilibrium, Alfven continua and eigenmodes, through to linear growth and nonlinear saturation of a toroidal Alfven eigenmode (TAE); this i…
Preprint PublishedP. Helander F.I. Parra S.L. Newton
The bootstrap current and flow velocity of a low-collisionality stellarator plasma are calculated. As far as possible, the analysis is carried out in a uniform way across all low-collisionality regimes in general stellarator geometry, assuming only that the confinement is good enough that the plasma is approximately in local thermodynamic equilibri…
Preprint Published