E. G. Highcock A. A. Schekochihin S. C. Cowley M. Barnes F. I. Parra C. M. Roach W. Dorland
Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that magnetic field pitch/inverse aspect ratio is a critical control parameter for sheared tokamak…
PublishedB. Lloyd R.J. Akers F. Alladio S. Allan Et Al
Major developments on MAST have enabled important advances in support of ITER and the physics basis of a spherical tokamak (ST) based component test facility (CTF), as well as providing new insight into underlying tokamak physics. For example, L-H transition studies benefit from high spatial and temporal resolution measurements of pedestal profile …
PublishedJ. Vallory H. Boyer F. Moreno
The Joint European Torus (JET) operates using deuterium as a fuel but has also operated in D-T mode where the fusion reaction is fuelled by deuterium and tritium. To justify the safety of D-D and D-T experiments, safety reports are produced to obtain approval for the experimental campaigns. The Safety Case has recently undergone a periodic safety r…
PublishedAnthony J. Webster
During plasma instabilities, “surface currents” can flow at the interface between the plasma and the surrounding vacuum, and in most cases, they are a harmless symptom of the instability that is causing them. Large instabilities can lead to “disruptions,” an abrupt termination of the plasma with the potential to damage the machine in which …
PublishedIT Chapman NR Walkden JP Graves C Wahlberg
Sheared toroidal rotation is found to increase the ideal external kink stability limit, thought to be the ultimate performance limit in fusion tokamaks. However, at rotation speeds approaching a significant fraction of the Alfv´en speed, the toroidal rotation shear drives a Kelvin-Helmholtzlike global plasma instability. Optimising the rotation pr…
PublishedF. Militello W.Fundamenski V. Naulin A.H. Nielsen
The L-mode interchange turbulence in the edge and Scrape Off Layer of the tight aspect ratio tokamak MAST is investigated numerically. The dynamics of the boundary plasma is studied using the 2D drift-fluid code ESEL, which has previously shown good agreement with large aspect ratio machines. In this context, a MAST-TCV comparison is presented in o…
PublishedC. Arnas C. Pardanaud C. Martin P. Roubin G. De Temmerman et al.
Among dust particles of various origins collected in the MAST vessel, large quantities of carbon nanoparticles are observed. They are produced in the coldest plasma regions from the nucleation of carbonaceous species originating from physical and chemical erosion of the graphitic plasma facing components. On the other hand, laboratory plasmas studi…
PublishedL W Packer M Gilbert S Hughes S Lilley R Pampin J-C Sublet
In support of the technological requirements for fusion, the UK fusion technology programme is conducting several experiments using the ASP DT neutron irradiation facility at AWE Aldermaston. The present experimental programme covers two key areas of technology development: improving the quality of nuclear cross-section data required for fusion-rel…
PublishedR. V. Bravenec J. Candy M. Barnes C. Holland
Verification of nonlinear microstability codes is a necessary step before comparisons or predictions of turbulent transport in toroidal devices can be justified. By verification we mean demonstrating that a code correctly solves the mathematical model upon which it is based. Some degree of verification can be accomplished indirectly from analytical…
Published