Surface heat flux feedback controlled impurity seeding experiments with Alcator C-Mod's high-Z vertical target plate divertor: performance, limitations and implications for fusion power reactors

被引:19
作者
Brunner, D. [1 ]
Wolfe, S. M. [1 ]
LaBombard, B. [1 ]
Kuang, A. Q. [1 ]
Lipschultz, B. [2 ]
Reinke, M. L. [3 ]
Hubbard, A. [1 ]
Hughes, J. [1 ]
Mumgaard, R. T. [1 ]
Terry, J. L. [1 ]
Umansky, M. V. [4 ]
机构
[1] MIT, Plasma Sci & Fus Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA
[2] Univ York, York Plasma Inst, York YO10 5DQ, N Yorkshire, England
[3] Oak Ridge Natl Lab, Oak Ridge, TN USA
[4] Lawerence Livermore Natl Lab, Livermore, CA USA
关键词
tokamak; heat flux; feedback; CHAPTER; 4; CONFINEMENT; OPERATION; TRANSPORT;
D O I
10.1088/1741-4326/aa7923
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
The Alcator C-Mod team has recently developed a feedback system to measure and control surface heat flux in real-time. The system uses real-time measurements of surface heat flux from surface thermocouples and a pulse-width modulated piezo valve to inject low-Z impurities (typically N-2) into the private flux region. It has been used in C-Mod to mitigate peak surface heat fluxes >40 MW m(-2) down to < 10 MW m(-2) while maintaining excellent core confinement, H-98 > 1. While the system works quite well under relatively steady conditions, use of it during transients has revealed important limitations on feedback control of impurity seeding in conventional vertical target plate divertors. In some cases, the system is unable to avoid plasma reattachment to the divertor plate or the formation of a confinement-damaging x-point MARFE. This is due to the small operational window for mitigated heat flux in the parameters of incident plasma heat flux, plasma density, and impurity density as well as the relatively slow response of the impurity gas injection system compared to plasma transients. Given the severe consequences for failure of such a system to operate reliably in a reactor, there is substantial risk that the conventional vertical target plate divertor will not provide an adequately controllable system in reactor-class devices. These considerations motivate the need to develop passively stable, highly compliant divertor configurations and experimental facilities that can test such possible solutions.
引用
收藏
页数:12
相关论文
共 57 条
[31]   ADX: a high field, high power density, advanced divertor and RF tokamak [J].
LaBombard, B. ;
Marmar, E. ;
Irby, J. ;
Terry, J. L. ;
Vieira, R. ;
Wallace, G. ;
Whyte, D. G. ;
Wolfe, S. ;
Wukitch, S. ;
Baek, S. ;
Beck, W. ;
Bonoli, P. ;
Brunner, D. ;
Doody, J. ;
Ellis, R. ;
Ernst, D. ;
Fiore, C. ;
Freidberg, J. P. ;
Golfinopoulos, T. ;
Granetz, R. ;
Greenwald, M. ;
Hartwig, Z. S. ;
Hubbard, A. ;
Hughes, J. W. ;
Hutchinson, I. H. ;
Kessel, C. ;
Kotschenreuther, M. ;
Leccacorvi, R. ;
Lin, Y. ;
Lipschultz, B. ;
Mahajan, S. ;
Minervini, J. ;
Mumgaard, R. ;
Nygren, R. ;
Parker, R. ;
Poli, F. ;
Porkolab, M. ;
Reinke, M. L. ;
Rice, J. ;
Rognlien, T. ;
Rowan, W. ;
Shiraiwa, S. ;
Terry, D. ;
Theiler, C. ;
Titus, P. ;
Umansky, M. ;
Valanju, P. ;
Walk, J. ;
White, A. ;
Wilson, J. R. .
NUCLEAR FUSION, 2015, 55 (05)
[32]   A novel tracer-gas injection system for scrape-off layer impurity transport and screening experiments [J].
Labombard, B ;
Gangadhara, S ;
Lipschultz, B ;
Lisgo, S ;
Pappas, DA ;
Pitcher, CS ;
Stangeby, P ;
Terry, J .
JOURNAL OF NUCLEAR MATERIALS, 1999, 266 :571-576
[33]   Disruptions in ITER and strategies for their control and mitigation [J].
Lehnen, M. ;
Aleynikova, K. ;
Aleynikov, P. B. ;
Campbell, D. J. ;
Drewelow, P. ;
Eidietis, N. W. ;
Gasparyan, Yu. ;
Granetz, R. S. ;
Gribov, Y. ;
Hartmann, N. ;
Hollmann, E. M. ;
Izzo, V. A. ;
Jachmich, S. ;
Kim, S. -H. ;
Kocan, M. ;
Koslowski, H. R. ;
Kovalenko, D. ;
Kruezi, U. ;
Loarte, A. ;
Maruyama, S. ;
Matthews, G. F. ;
Parks, P. B. ;
Pautasso, G. ;
Pitts, R. A. ;
Reux, C. ;
Riccardo, V. ;
Roccella, R. ;
Snipes, J. A. ;
Thornton, A. J. ;
de Vries, P. C. .
JOURNAL OF NUCLEAR MATERIALS, 2015, 463 :39-48
[34]   Divertor physics research on Alcator C-Mod [J].
Lipschultz, B. ;
LaBombard, B. ;
Terry, J. L. ;
Boswell, C. ;
Hutchinson, I. H. .
FUSION SCIENCE AND TECHNOLOGY, 2007, 51 (03) :369-389
[35]   Divertor tungsten tile melting and its effect on core plasma performance [J].
Lipschultz, B. ;
Coenen, J. W. ;
Barnard, H. S. ;
Howard, N. T. ;
Reinke, M. L. ;
Whyte, D. G. ;
Wright, G. M. .
NUCLEAR FUSION, 2012, 52 (12)
[36]   Sensitivity of detachment extent to magnetic configuration and external parameters [J].
Lipschultz, Bruce ;
Parra, Felix I. ;
Hutchinson, Ian H. .
NUCLEAR FUSION, 2016, 56 (05)
[37]   Chapter 4: Power and particle control [J].
Loarte, A. ;
Lipschultz, B. ;
Kukushkin, A. S. ;
Matthews, G. F. ;
Stangeby, P. C. ;
Asakura, N. ;
Counsell, G. F. ;
Federici, G. ;
Kallenbach, A. ;
Krieger, K. ;
Mahdavi, A. ;
Philipps, V. ;
Reiter, D. ;
Roth, J. ;
Strachan, J. ;
Whyte, D. ;
Doerner, R. ;
Eich, T. ;
Fundamenski, W. ;
Herrmann, A. ;
Fenstermacher, M. ;
Ghendrih, P. ;
Groth, M. ;
Kirschner, A. ;
Konoshima, S. ;
LaBombard, B. ;
Lang, P. ;
Leonard, A. W. ;
Monier-Garbet, P. ;
Neu, R. ;
Pacher, H. ;
Pegourie, B. ;
Pitts, R. A. ;
Takamura, S. ;
Terry, J. ;
Tsitrone, E. .
NUCLEAR FUSION, 2007, 47 (06) :S203-S263
[38]   High confinement/high radiated power H-mode experiments in Alcator C-Mod and consequences for International Thermonuclear Experimental Reactor (ITER) QDT=10 operation [J].
Loarte, A. ;
Hughes, J. W. ;
Reinke, M. L. ;
Terry, J. L. ;
LaBombard, B. ;
Brunner, D. ;
Greenwald, M. ;
Lipschultz, B. ;
Ma, Y. ;
Wukitch, S. ;
Wolfe, S. .
PHYSICS OF PLASMAS, 2011, 18 (05)
[39]   Three-dimensional simulation of H-mode plasmas with localized divertor impurity injection on Alcator C-Mod using the edge transport code EMC3-EIRENE [J].
Lore, J. D. ;
Reinke, M. L. ;
Brunner, D. ;
LaBombard, B. ;
Lipschultz, B. ;
Terry, J. ;
Pitts, R. A. ;
Feng, Y. .
PHYSICS OF PLASMAS, 2015, 22 (05)
[40]   Demonstration of real-time control of impurity seeding plus outboard strike-point sweeping in JET ELMy H-mode plasmas [J].
Maddison, G. P. ;
Giroud, C. ;
McCormick, G. K. ;
Alper, B. ;
Arnoux, G. ;
Belo, P. C. da Silva Aresta ;
Beurskens, M. N. A. ;
Boboc, A. ;
Brett, A. ;
Brezinsek, S. ;
Coffey, I. ;
Devaux, S. ;
Devynck, P. ;
Eich, T. ;
Felton, R. ;
Fundamenski, W. ;
Harling, J. ;
Huber, A. ;
Jachmich, S. ;
Joffrin, E. ;
Lomas, P. J. ;
Monier-Garbet, P. ;
Morgan, P. D. ;
Stamp, M. F. ;
Telesca, G. ;
Thomsen, H. ;
Voitsekhovitch, I. .
NUCLEAR FUSION, 2011, 51 (08)