J. S. Wróbel D. Nguyen-Manh M. Y. Lavrentiev M. Muzyk S. L. Dudarev
The phase stability of fcc and bcc magnetic binary Fe-Cr, Fe-Ni, and Cr-Ni alloys, and ternary Fe-Cr-Ni alloys is investigated using a combination of density functional theory (DFT), cluster expansion (CE), and magnetic cluster expansion (MCE) approaches. Energies, magnetic moments, and volumes of more than 500 alloy structures have been evaluated …
Preprint PublishedS. C. Chapman R. O. Dendy T. N. Todd N. W. Watkins F. A. Calderon J. Morris JET Contributors
A global signature of the build-up to an intrinsic edge localized mode (ELM) is found in the temporal analytic phase of signals measured in full flux azimuthal loops in the divertor region of JET. Toroidally integrating, full flux loop signals provide a global measurement proportional to the voltage induced by changes in poloidal magnetic flux; the…
PublishedJ. Wesson
Landau’s calculation of electron plasma oscillations demonstrated the phenomenon now known as Landau damping.1 The calculation used a Fourier-Laplace transform and regarded the electron velocity as complex in order to properly locate the pole in the complex frequency plane that gives the dispersion relation containing the wave damping. Here, the …
Preprint PublishedG. Z. Hao Y. Q. Liu A. K. Wang M. Xu H. P. Qu X. D. Peng Z. H. Wang J. Q. Xu X. M. Qiu
The MARS-F code [Y. Q. Liu et al., Phys. Plasmas 7, 3681 (2000)] is applied to numerically investigate the effect of the plasma pressure on the tearing mode stability as well as the tearing mode-induced electromagnetic torque, in the presence of a resistive wall. The tearing mode with a complex eigenvalue, resulted from the favorable averaged curva…
PublishedG. G. Plunk P. Helander P. Xanthopoulos J. W. Connor
We investigate the linear theory of the ion-temperature-gradient (ITG) mode, with the goal of developing a general understanding that may be applied to stellarators. We highlight the Wendelstein 7X (W7-X) device. Simple fluid and kinetic models that follow closely from existing literature are reviewed and two new first-principle models are presente…
PublishedF. Villone G. Calabrò G. Marchiori S. Mastrostefano G. Vlad T. Bolzonella F. Crisanti V. Fusco Y. Q. Liu P. Mantica L. Marrelli P. Martin
One of the main FAST (Fusion Advanced Studies Torus) goals is to have a flexible experiment capable to test tools and scenarios for safe and reliable tokamak operation, in order to support ITER and help the final DEMO design. In particular, in this paper, we focus on operation close to a possible border of stability related to low-q operation. To t…
PublishedP. Jacquet V. Bobkov L. Colas A. Czarnecka E. Lerche M.-L. Mayoral I. Monakhov D. Van-Eester G. Arnoux S. Brezinsek M. Brix A.-L. Campergue S. Devaux P. Drewelow M. Graham C. C. Klepper A. Meigs D. Milanesio J. Mlynar T. Pütterich A. S
In 2011/12, JET started operation with its new ITER-Like Wall (ILW) made of a tungsten (W) divertor and a beryllium (Be) main chamber wall. The impact of the new wall materials on the JET Ion Cyclotron Resonance Frequency (ICRF) operation is assessed and some important properties of JET plasmas heated with ICRF are highlighted. A 20% reduction of t…
PublishedS. C. Chapman R. O. Dendy T. N. Todd N. W. Watkins A. J. Webster F. Calderon J. Morris JET EFDA Contributors
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in …
PublishedD.R. Mason X. Yi M.A. Kirk S.L. Dudarev
Using in situ transmission electron microscopy (TEM), we have observed nanometre scale dislocation loops formed when an ultra-high-purity tungsten foil is irradiated with a very low fluence of self-ions. Analysis of the TEM images has revealed the largest loops to be predominantly of prismatic 1/2{111} type and of vacancy character. The formation o…
PublishedP. Jacquet V. Bobkov S. Brezinsek M. Brix A-L. Campergue L. Colas A. Czarnecka P. Drewelow M. Graham C. C. Klepper E. Lerche M.-L. Mayoral A. Meigs D. Milanesio I. Monakhov J. Mlynar T. Pütterich A. Sirinelli D. Van-Eester JET-EFDA
In 2011/12, JET started operation with its new ITER-Like Wall (ILW) made of a tungsten (W) divertor and a beryllium (Be) main chamber wall. The impact of the new wall material on the JET Ion Cyclotron Resonance Frequency (ICRF) operation was assessed and also the properties of JET plasmas heated with ICRF were studied. No substantial change of the …
Published