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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
Times Cited Count：22 Percentile：97.38(Physics, Fluids & Plasmas)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.
Kamiya, Kensaku; Asakura, Nobuyuki; Boedo, J. A.*; Eich, T.*; Federici, G.*; Fenstermacher, M.*; Finken, K.*; Herrmann, A.*; Terry, J.*; Kirk, A.*; et al.
Plasma Physics and Controlled Fusion, 49(7), p.s43 - s62, 2007/07
Times Cited Count：75 Percentile：91.75(Physics, Fluids & Plasmas)Edge Localized Mode (ELM) measurements in the tokamaks, including JT-60U, DIII-D, ASDEX-U and JET, are reviewed. The followings are outlines of this presentation. (1) ELM Types and basic scaling, (2) Small ELM regimes and ELM mitigation, (3) ELM filament formation and transverse motion, (4) Power deposition on divertor targets and main chamber wall.
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
Times Cited Count：859 Percentile：98.25(Physics, Fluids & Plasmas)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.
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
Times Cited Count：40 Percentile：78.1(Physics, Fluids & Plasmas)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.
Stober, J.*; Lomas, P. J.*; Saibene, G.*; Andrew, Y.*; Belo, P.*; Conway, G. D.*; Herrmann, A.*; Horton, L. D.*; Kempenaars, M.*; Koslowski, H.-R.*; et al.
Nuclear Fusion, 45(11), p.1213 - 1223, 2005/11
Times Cited Count：40 Percentile：76.37(Physics, Fluids & Plasmas)no abstracts in English
Loarte, A.*; Saibene, G.*; Sartori, R.*; Campbell, D.*; Becoulet, M.*; Horton, L.*; Eich, T.*; Herrmann, A.*; Matthews, G.*; Asakura, Nobuyuki; et al.
Plasma Physics and Controlled Fusion, 45(9), p.1549 - 1569, 2003/10
Times Cited Count：449 Percentile：99.72(Physics, Fluids & Plasmas)Analysis of Type I ELMs from ongoing experiments shows that ELM energy losses are correlated with the density and temperature of the pedestal plasma before the ELM crash. The Type I ELM plasma energy loss normalized to the pedestal energy is found to correlate across experiments with the collisionality of the pedestal plasma. Other parameters affect the ELM size such as the edge magnetic shear, etc, which influence the plasma volume affected by the ELMs. ELM particle losses are influenced by this ELM affected volume and are weakly dependent on other pedestal plasma parameters. In JET and DIII-D, minimum Type I ELMs with energy losses acceptable for ITER were found, that do not affect the plasma temperature. The duration of the divertor ELM power pulse is correlated with the typical ion transport time from the pedestal to the divertor target and not with the duration of the ELM associated MHD activity. Extrapolation of the present experimental results to ITER is summarized.
Loarte, A.*; Saibene, G.*; Sartori, R.*; Becoulet, M.*; Horton, L.*; Eich, T.*; Herrmann, A.*; Laux, M.*; Matthews, G.*; Jachmich, S.*; et al.
Journal of Nuclear Materials, 313-316, p.962 - 966, 2003/03
Times Cited Count：114 Percentile：98.43(Materials Science, Multidisciplinary)no abstracts in English
Asakura, Nobuyuki; Loarte, A.*; Porter, G.*; Philipps, V.*; Lipschultz, B.*; Kallenbach, A.*; Matthews, G.*; Federici, G.*; Kukushkin, A.*; Mahdavi, A.*; et al.
IAEA-CN-94/CT/P-01, 5 Pages, 2002/00
Three important physics issues for the ITER divertor design and operation are summarized based on the experimental and numerical work from multi-machine database (JET, JT-60U, ASDEX Upgrade, DIII-D, Alcator C-Mod and TEXTOR). (i) The energy load associated with Type-I ELMs is of great concern for the lifetime of the ITER divertor target. In order to understand the physics base of the scaling models, the ELM heat and particle transport to the divertor is investigated. Convective transport during ELMs plays an important role in heat transport to the divertor. (ii) Determination of the SOL flow pattern and the driving mechanism has progressed experimentally and numerically. Influences of the drift effects on the SOL and divertor plasma transport were discussed. (iii) Characteristics of chemical yield at two different deposited carbon surfaces, i.e. erosion- and redeposition-dominated areas, have been studied. Progress of understanding the chemical erosion is reviewed.
