H. Tojo A. Ejiri M. P. Gryaznevich Y. Takase Y. Adachi
A method to determine the poloidal mode number m in a spherical tokamak based on magnetic probe data was developed. Perturbed magnetic fields at Mirnov coils are calculated for distributed helical filamentary currents on rational surfaces assuming the maximum current amplitude, m and n toroidal mode number, and the toroidal location of the filament…
PublishedM. Mrovec R. Gröger A. G. Bailey D. Nguyen-Manh C. Elsässer V. Vitek
We present a bond-order potential BOP for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure an…
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…
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 …
PublishedChristian Lang Se Ahn Song Duc Nguyen Manh David J. H. Cockayne
The structural changes during the phase change between the amorphous and crystalline phase in Ge 2 Sb 2 Te 5 have been the subject of intense study due to the importance of Ge 2 Sb 2 Te 5 in phase change memory devices. In our study, the energetics of the transition between the crystalline and the amorphous phase of Ge 2 Sb 2 Te 5 is explored using…
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…
PublishedP. 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…
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…
PublishedM. K. Lilley S. E. Sharapov
A discrete spectrum of compressional Alfvén eigenmodes and ion-ion hybrid eigenmodes is found to exist above the tritium ion cyclotron frequency in the deuterium-tritium D-T plasma of a spherical tokamak power plant STPP [H. R. Wilson and et al. , 19th IAEA Fusion Energy Conference IAEA, Lyon, France, (2002), No. FT/1-4]. An equilibrium magnetic w…
Published