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Bandyopadhyay, I.*; Gerhardt, S.*; Jardin, S.*; Sayer, R. O.*; Nakamura, Yukiharu*; Miyamoto, Seiji; Pautasso, G.*; Sugihara, Masayoshi*; ASDEX Upgrade Team*; NSTX Team*
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2010/10
Vertical Displacement Events (VDEs) and Major Disruptions (MDs) of the plasma current will induce large electromagnetic forces on the ITER machine. Estimation of these forces based on accurate modeling of these events is necessary for a robust ITER design. Originally the estimates for electromagnetic forces on ITER were carried out with the help of DINA simulations. However, since simulations of these events may be significantly influenced by model assumptions of a given code it is important to validate the results against other codes like TSC, as also benchmark and update the codes with experimental data. In this paper, we present TSC modeling of the VDE and MD events in NSTX and ASDEX-U devices, which help in improving and validating the models used in the code. The predictive modeling results for ITER with the updated code, including the force predictions, are also presented.
Nakamura, Yukiharu*; Pautasso, G.*; Sugihara, Masayoshi*; Miyamoto, Seiji; Toshimitsu, Shinichi; Yoshino, Ryuji; ASDEX Upgrade Team*
Proceedings of 37th European Physical Society Conference on Plasma Physics (EPS 2010) (CD-ROM), 4 Pages, 2010/06
Of particular importance for the assessment of electromagnetic loads on vacuum vessel and in-vessel components of ITER is the halo current which achieves a maximum during VDEs (VDE: vertical displacement event). However, halo current models have a limited development so far with a few exceptions such as a validation study of the JT-60U halo current modelling using the DINA code. Recently, several experimental groups have prepared systematic halo current data, and further model development and validation with these data need to be performed using an axisymmetric, two-dimensional, free boundary code, TSC. To enhance an understanding of the maximum halo current and large vertical shifts, a reference discharge was selected from those included in the ASDEX upgrade disruption database. Systematic TSC simulations were performed to mimic the observation of a slow VDE of hot plasma and an ensuing fast downward-going VDE during a subsequent plasma current quench. Careful parameter adjustment of the temperature and width of the halo region was examined to mimic measurements of the halo current. A spontaneous, downward-going VDE was reproduced accurately in a manner that closely resembled experimental observations.
Hender, T. C.*; Wesley, J. C.*; Bialek, J.*; Bondeson, A.*; Boozer, A. H.*; Buttery, R. J.*; Garofalo, A.*; Goodman, T. P.*; Granetz, R. S.*; Gribov, Y.*; et al.
Nuclear Fusion, 47(6), p.S128 - S202, 2007/06
Times Cited Count：916 Percentile：100(Physics, Fluids & Plasmas)no abstracts in English
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.
Nakamura, Yukiharu; Pautasso, G.*; Gruber, O.*; Jardin, S. C.*
Plasma Physics and Controlled Fusion, 44(8), p.1471 - 1481, 2002/08
Times Cited Count：12 Percentile：38.18(Physics, Fluids & Plasmas)no abstracts in English
Nakamura, Yukiharu; Yoshino, Ryuji; Granetz, R. S.*; Pautasso, G.*; Gruber, O.*; Jardin, S. C.*
Purazuma, Kaku Yugo Gakkai-Shi, 78(4), p.347 - 355, 2002/04
no abstracts in English
