Wiesen, S.*; Brezinsek, S.*; Jrvinen, A.*; Eich, T.*; Fundamenski, W.*; Huber, A.*; Parail, V.*; Corrigan, G.*; Hayashi, Nobuhiko; JET-EFDA Contributors*
Plasma Physics and Controlled Fusion, 53(12), p.124039_1 - 124039_12, 2011/12
Kirk, A.*; Asakura, Nobuyuki; Boedo, J. A.*; Beurskens, M.*; Counsell, G. F.*; Eich, T.*; Fundamenski, W.*; Herrmann, A.*; Kamada, Yutaka; Leonard, A. W.*; et al.
Journal of Physics; Conference Series, 123, p.012011_1 - 012011_10, 2008/00
A comparison of the spatial and temporal evolution of the filamentary structures observed during type I ELMs is presented from a variety of diagnostics and machines. There is evidence that these filaments can be detected inside the LCFS prior to ELMs. The filaments do not have a circular cross section instead they are elongated in the perpendicular (poloidal) direction and this size appears to increase linearly with the minor radius of the machine. The filaments start rotating toroidally/poloidally with velocities close to that of the pedestal. This velocity then decreases as the filaments propagate radially. It is most likely that the filaments have at least their initial radial velocity when they are far out into the SOL. The dominant loss mechanism is through parallel transport and the transport to the wall is through the radial propagation of these filaments. Measurements of the filament energy content show that each filament contains up to 2.5 % of the energy released by the ELM.
Loarte, A.*; Lipschultz, B.*; Kukushkin, A. S.*; Matthews, G. F.*; Stangeby, P. C.*; Asakura, Nobuyuki; Counsell, G. F.*; Federici, G.*; Kallenbach, A.*; Krieger, K.*; et al.
Nuclear Fusion, 47(6), p.S203 - S263, 2007/06
Progress, since the ITER Physics Basis publication (1999), in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in ITER is described. Significant progress in experiment area: energy and particle transport, the interaction of plasmas with the main chamber material elements, ELM energy deposition on material elements and the transport mechanism, the physics of plasma detachment and neutral dynamics, the erosion of low and high Z materials, their transport to the core plasma and their migration at the plasma edge, retention of tritium in fusion devices and removal methods. This progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction. The implications for the expected performance in ITER and the lifetime of the plasma facing materials are discussed.
Chankin, A. V.*; Coster, D. P.*; Asakura, Nobuyuki; Bonnin, X.*; Conway, G. D.*; Corrigan, G.*; Erents, S. K.*; Fundamenski, W.*; Horacek, J.*; Kallenbach, A.*; et al.
Nuclear Fusion, 47(5), p.479 - 489, 2007/05
Radial electric field in known to be one of the drivers for the parallel ion flow in the SOL. It contributes to the ion Pfirsch-Schluter flow and determines the return parallel flow compensating poloidal ExB drift. It was established recently that 2D fluid codes EDGE2D and SOLPS underestimate the predicted Er in the SOL compared to experimentally measured values. The present work demonstrates that this underestimate can be responsible for the large discrepancy between measured and simulated parallel ion flows in the SOL. Provided radial electric field was modelled correctly by the codes, an increase in the predicted Mach number of the parallel ion flow by up to a factor 3 for the JET could be expected. This would entirely eliminate the difference between the experimentally determined part of the ion flow that depends on the toroidal field direction, and the modelled ion flow attributed to drifts. Discrepancy between measured and simulated flows in ASDEX-Upgrade was also reduced.
Lipschultz, B.*; Asakura, Nobuyuki; Bonnin, X.*; Coster, D. P.*; Counsell, G.*; Doerner, R.*; Dux, R.*; Federici, G.*; Fenstermacher, M. E.*; Fundamenski, W.*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
The work of the ITPA SOL/divertor group is reviewed. The high-n nature of ELMs has been elucidated and new measurements have determined that they carry 10-20% of the ELM energy to the far SOL with implications for ITER limiters and the upper divertor. Analysis of ELM measurements imply that the ELM continuously loses energy as it travels across the SOL. The prediction of ITER divertor disruption power loads have been reduced as a result of finding that the divertor footprint broadens during the thermal quench and that the plasma can lose up to 80% of its thermal energy before the thermal quench (not for VDEs or ITBs). Disruption mitigation through massive gas puffing has been successful at reducing divertor heat loads but estimates of the effect on the main chamber walls indicate 10s of kG of Be would be melted/mitigation. Long-pulse studies have shown that the fraction of injected gas that can be recovered after a discharge decreases with discharge length. The use of mixed materials gives rise to a number of potential processes.
Leonard, A. W.*; Asakura, Nobuyuki; Boedo, J. A.*; Becoulet, M.*; Counsell, G. F.*; Eich, T.*; Fundamenski, W.*; Herrmann, A.*; Horton, L. D.*; Kamada, Yutaka; et al.
Plasma Physics and Controlled Fusion, 48(5A), p.A149 - A162, 2006/05
This report summarizes Type I edge localized mode (ELM) dynamics measurements from a number of tokamaks. Several transport mechanisms are conjectured to be responsible for ELM transport, including convective transport due to filamentary structures ejected from the pedestal, parallel transport due to edge ergodization or magnetic reconnection and turbulent transport driven by the high edge gradients when the radial electric field shear is suppressed. The experimental observations are assessed for their validation, or conflict, with these ELM transport conjectures.
Itami, Kiyoshi; Coad, P.*; Fundamenski, W.*; Ingesson, C.*; Lingertat, J.*; Matthews, G. F.*; Tabasso, A.*
Journal of Nuclear Materials, 290-293, p.633 - 638, 2001/03
no abstracts in English