Andrea Murari Guido Vagliasindi Sebastiano De Fiore Eleonora Arena Paolo Arena Luigi Fortuna Y. Andrew M. Johnson JET-EFDA Contributors
Dynamical systems are often considered immune from memory effects, i.e., the dependence of their time evolution on the previous history. This assumption has been tested for two phenomena in nuclear fusion that are believed to sometimes show sensitivity to the previous history of the discharge: disruptions and the transition from the L mode to the H…
PublishedIT Chapman M-D Hua SD Pinches RJ Akers AR Field JP Graves RJ Hastie CA Michael The Mast Team
MAST plasmas with a safety factor above unity and a profile with either weakly reversed shear, or broad low shear regions, regularly exhibit long-lived saturated ideal magnetohydrodynamic (MHD) instabilities. The toroidal rotation is flattened in the presence of such perturbations and the fast ion losses are enhanced. These ideal modes, distinguish…
PublishedE. G. Highcock M. Barnes A. A. Schekochihin F. I. Parra C. M. Roach S.C. Cowley
The effect of flow shear on turbulent transport in tokamaks is studied numerically in the experimentally relevant limit of zero magnetic shear. It is found that the plasma is linearly stable for all nonzero flow shear values, but that subcritical turbulence can be sustained nonlinearly at a wide range of temperature gradients. Flow shear increases …
PublishedN. J. Conway
A motional Stark effect MSE diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of 2.5 cm, and time resolution of 1 ms at angular noise levels of 0.5°. Conventional albeit very narrow interference filters isolate or polarized emission. Avalanche photodiode detectors with di…
PublishedK. G. McClements & R. J. Mckay
Impurity ions with sufficiently high mass in toroidally-rotating tokamak plasmas are deeply trapped by a centrifugal potential well in the outer plasma midplane, with a bounce period that is shorter than both the bounce period of magnetically-trapped ions and the collision time. As a result trace impurity ions can undergo collisional transport at a…
PublishedP. U. Lamalle B. Beaumont T. Gassmann F. Kazarian B. Arambhadiya et al.
The ITER Ion Cyclotron Heating and Current Drive system will deliver 20MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of reqiurements …
PublishedJ. Garcia J. F. Artaud V. Basiuk M. Brix J. Decker et al.
The impact of the Radio Frequency heating and current drive systems on the ITER advanced scenarios is analyzed by means of the CRONOS suite of codes for integrated tokamak modelling. As a first step, the code is applied to analyze a high power advanced scenario discharge of JET in order to validate both the heating and current drive modules and the…
PublishedM. Bécoulet G. Huysmans X. Garbet E. Nardon D. Howell A.Garofalo M. Schaffer T. Evans K. Shaing A. Cole J.-K. Park P. Cahyna
Non-linear reduced MHD modelling of the response of a toroidally rotating plasma on Resonant Magnetic Perturbations (RMPs) is presented for DIII-D and ITER typical parameter. The non-linear cylindrical reduced MHD (RMHD) code was adapted to take into account toroidal rotation and plasma braking mechanisms such as resonant braking (~jxB) and the Neo…
PublishedAnthony J. Webster
This paper describes physically and mathematically how the plasma-vacuum boundary of a tokamak plasma equilibrium can be perturbed to form a separatrix with an X-point, while having an otherwise negligible affect on the plasma equilibrium. A deliberate consequence of the technique is that the radial and poloidal extent of the perturbed region may b…
Published