P. M. Derlet D. Nguyen-Manh S. L. Dudarev
We investigate the structure and mobility of single self-interstitial atom and vacancy defects in bodycentered- cubic transition metals forming groups 5B vanadium, niobium, and tantalum and 6B chromium, molybdenum, and tungsten of the Periodic Table. Density-functional calculations show that in all these metals the axially symmetric 111 self-inters…
PublishedElizabeth Surrey
A model of the space charge neutralization of negative ion beams, developed from the model due to Holmes, is applied to the ITER heating and diagnostic beams. The Holmes model assumed that the plasma electron temperature was derived from the stripped electrons. This is shown to be incorrect for the ITER beams and the plasma electron temperature is …
PublishedJ. A. Merrifield S. C. Chapman R. O. Dendy
Direct numerical simulations DNS provide a means to test phenomenological models for the scaling properties of intermittent MHD turbulence. The well-known model of She and Leveque, when generalized to MHD, is in good agreement with the DNS in three dimensions, however, it does not coincide with DNS in two dimensions 2D. This is resolved here using …
PublishedR. S. Hemsworth H. P. L. De Esch M. Kovari L. Svensson F. Villecroze
The development of the Single Aperture. Single Gap 1 MV accelerator (SINGAP) is being carried out on the 1 MV test bed at the DRFC, CEA Cadarache, France. This paper reports on the latest performance achieved with the prototype, "ITER-like" accelerator, 730 keV, 120 A/m 2 D", and of on-going measurements of the beam "halo" fraction, »10%. It revie…
PublishedJ. W. Connor R. J. Hastie A. J. Webster
The destabilization of ideal magnetohydrodynamic ballooning modes at finite rotation shear is demonstrated for the model s - equilibrium by exploiting low magnetic shear, s , to simplify the two-dimensional stability problem to a one-dimensional eigenvalue problem. This simpler calculation captures the same features as exhibited by a full two-dimen…
PublishedI. T. Chapman S. D. Pinches L. C. Appel R. J. Hastie T. C. Hender S. Saarelma S. E. Sharapov I. Voitsekhovitch J. P. Graves
Recent advances in modeling the effects of anisotropic energetic ion distributions have enabled the development of a complete coherent physics explanation of sawtooth stabilization in both conventional and spherical tokamaks. As an example, a complete model has been developed to explain the asymmetric stabilization of sawteeth with respect to neutr…
PublishedV. Shevchenko G. Cunningham A. Gurchenko E. Gusakov B. Lloyd M. O’Brien A. Saveliev A. Surkov F.Volpe M. Walsh
There is a comprehensive, closely-interlinked electron Bernstein wave (EBW) programme on MAST covering heating experiments, plasma start-up studies, plasma emission measurements, theory and modelling. In this paper we report on proof-of-principle EBW heating experiments conducted on MAST with a 60 GHz, 1 MW gyrotron complex. A 28 GHz (200 kW) EBW s…
PublishedM. Romanelli G. Regnoli C. Bourdelle
The linear stability of dissipative drift electrostatic modes in tokamak plasmas is studied numerically with an extended version of the gyrokinetic code [Kinezero C. Bourdelle and et al. , Nucl. Fusion 42 , 892 (2002)] including a modified Krook collision operator to account for collisional effects on the trapped electron response. This new version…
PublishedF. Louche P.U. Lamalle F. Durodié A. Borthwick
We present the results of a numerical investigation of the interaction between the ITER ICRF antenna plug (external matching option) and the surrounding wall blanket modules with the commercial software CST Microwave Studio (MWS). In particular we study the RF currents circulating on and between these modules with a simplified rectangular model of …
Published