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Title: Developing snowflake divertor physics basis in the DIII-D, NSTX and NSTX-U tokamaks aimed at the divertor power exhaust solution [Snowflake divertor experiments in the DIII-D, NSTX and NSTX-U tokamaks aimed at the development of the divertor power exhaust solution]

Experimental results from the National Spherical Torus Experiment (NSTX), a medium-size spherical tokamak with a compact divertor, and DIII-D, a large conventional aspect ratio tokamak, demonstrate that the snowflake (SF) divertor configuration may provide a promising solution for mitigating divertor heat loads and target plate erosion compatible with core H-mode confinement in future fusion devices, where the standard radiative divertor solution may be inadequate. In NSTX, where the initial high-power SF experiment were performed, the SF divertor was compatible with H-mode confinement, and led to the destabilization of large ELMs. However, a stable partial detachment of the outer strike point was also achieved where inter-ELM peak heat flux was reduced by factors 3-5, and peak ELM heat flux was reduced by up to 80% (cf. standard divertor). The DIII-D studies show the SF divertor enables significant power spreading in attached and radiative divertor conditions. Results include: compatibility with the core and pedestal, peak inter-ELM divertor heat flux reduction due to geometry at lower n e, and ELM energy and divertor peak heat flux reduction, especially prominent in radiative D 2-seeded SF divertor, and nearly complete power detachment and broader radiated power distribution in the radiative D 2-seeded SF divertor atmore » P SOL = 3 - 4 MW. A variety of SF configurations can be supported by the divertor coil set in NSTX Upgrade. Edge transport modeling with the multi-fluid edge transport code UEDGE shows that the radiative SF divertor can successfully reduce peak divertor heat flux for the projected P SOL ≃9 MW case. In conclusion, the radiative SF divertor with carbon impurity provides a wider n e operating window, 50% less argon is needed in the impurity-seeded SF configuration to achieve similar q peak reduction factors (cf. standard divertor).« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] more »;  [3] ;  [3] ;  [4] ;  [4] ;  [4] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] « less
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); College of William and Mary, Williamsburg, VA (United States)
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  4. General Atomics, San Diego, CA (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Univ. of Washington, Seattle, WA (United States)
  7. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Publication Date:
Grant/Contract Number:
FC02-04ER54698
Type:
Accepted Manuscript
Journal Name:
2015 IEEE 26th Symposium on Fusion Engineering (SOFE)
Additional Journal Information:
Journal Name: 2015 IEEE 26th Symposium on Fusion Engineering (SOFE); Conference: 2015 IEEE 26. Symposium on Fusion Engineering (SOFE), Austin, TX (United States), 31 May-4 Jun 2015
Research Org:
General Atomics, San Diego, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1373886

Soukhanovskii, V. A., Allen, S. L., Fenstermacher, M. E., Lasnier, C. J., Makowski, M. A., McLean, A. G., Meier, E. T., Meyer, W. H., Rognlien, T. D., Ryutov, D. D., Scotti, F., Kolemen, E., Bell, R. E., Diallo, A., Gerhardt, S., Kaita, R., Kaye, S., LeBlanc, B. P., Maingi, R., Menard, J. E., Podesta, M., Roquemore, A. L., Groebner, R. J., Hyatt, A. W., Leonard, A. W., Osborne, T. H., Petrie, T. W., Ahn, J. -W., Raman, R., and Watkins, J. G.. Developing snowflake divertor physics basis in the DIII-D, NSTX and NSTX-U tokamaks aimed at the divertor power exhaust solution [Snowflake divertor experiments in the DIII-D, NSTX and NSTX-U tokamaks aimed at the development of the divertor power exhaust solution]. United States: N. p., Web. doi:10.1109/SOFE.2015.7482263.
Soukhanovskii, V. A., Allen, S. L., Fenstermacher, M. E., Lasnier, C. J., Makowski, M. A., McLean, A. G., Meier, E. T., Meyer, W. H., Rognlien, T. D., Ryutov, D. D., Scotti, F., Kolemen, E., Bell, R. E., Diallo, A., Gerhardt, S., Kaita, R., Kaye, S., LeBlanc, B. P., Maingi, R., Menard, J. E., Podesta, M., Roquemore, A. L., Groebner, R. J., Hyatt, A. W., Leonard, A. W., Osborne, T. H., Petrie, T. W., Ahn, J. -W., Raman, R., & Watkins, J. G.. Developing snowflake divertor physics basis in the DIII-D, NSTX and NSTX-U tokamaks aimed at the divertor power exhaust solution [Snowflake divertor experiments in the DIII-D, NSTX and NSTX-U tokamaks aimed at the development of the divertor power exhaust solution]. United States. doi:10.1109/SOFE.2015.7482263.
Soukhanovskii, V. A., Allen, S. L., Fenstermacher, M. E., Lasnier, C. J., Makowski, M. A., McLean, A. G., Meier, E. T., Meyer, W. H., Rognlien, T. D., Ryutov, D. D., Scotti, F., Kolemen, E., Bell, R. E., Diallo, A., Gerhardt, S., Kaita, R., Kaye, S., LeBlanc, B. P., Maingi, R., Menard, J. E., Podesta, M., Roquemore, A. L., Groebner, R. J., Hyatt, A. W., Leonard, A. W., Osborne, T. H., Petrie, T. W., Ahn, J. -W., Raman, R., and Watkins, J. G.. 2016. "Developing snowflake divertor physics basis in the DIII-D, NSTX and NSTX-U tokamaks aimed at the divertor power exhaust solution [Snowflake divertor experiments in the DIII-D, NSTX and NSTX-U tokamaks aimed at the development of the divertor power exhaust solution]". United States. doi:10.1109/SOFE.2015.7482263. https://www.osti.gov/servlets/purl/1373886.
@article{osti_1373886,
title = {Developing snowflake divertor physics basis in the DIII-D, NSTX and NSTX-U tokamaks aimed at the divertor power exhaust solution [Snowflake divertor experiments in the DIII-D, NSTX and NSTX-U tokamaks aimed at the development of the divertor power exhaust solution]},
author = {Soukhanovskii, V. A. and Allen, S. L. and Fenstermacher, M. E. and Lasnier, C. J. and Makowski, M. A. and McLean, A. G. and Meier, E. T. and Meyer, W. H. and Rognlien, T. D. and Ryutov, D. D. and Scotti, F. and Kolemen, E. and Bell, R. E. and Diallo, A. and Gerhardt, S. and Kaita, R. and Kaye, S. and LeBlanc, B. P. and Maingi, R. and Menard, J. E. and Podesta, M. and Roquemore, A. L. and Groebner, R. J. and Hyatt, A. W. and Leonard, A. W. and Osborne, T. H. and Petrie, T. W. and Ahn, J. -W. and Raman, R. and Watkins, J. G.},
abstractNote = {Experimental results from the National Spherical Torus Experiment (NSTX), a medium-size spherical tokamak with a compact divertor, and DIII-D, a large conventional aspect ratio tokamak, demonstrate that the snowflake (SF) divertor configuration may provide a promising solution for mitigating divertor heat loads and target plate erosion compatible with core H-mode confinement in future fusion devices, where the standard radiative divertor solution may be inadequate. In NSTX, where the initial high-power SF experiment were performed, the SF divertor was compatible with H-mode confinement, and led to the destabilization of large ELMs. However, a stable partial detachment of the outer strike point was also achieved where inter-ELM peak heat flux was reduced by factors 3-5, and peak ELM heat flux was reduced by up to 80% (cf. standard divertor). The DIII-D studies show the SF divertor enables significant power spreading in attached and radiative divertor conditions. Results include: compatibility with the core and pedestal, peak inter-ELM divertor heat flux reduction due to geometry at lower ne, and ELM energy and divertor peak heat flux reduction, especially prominent in radiative D2-seeded SF divertor, and nearly complete power detachment and broader radiated power distribution in the radiative D2-seeded SF divertor at PSOL = 3 - 4 MW. A variety of SF configurations can be supported by the divertor coil set in NSTX Upgrade. Edge transport modeling with the multi-fluid edge transport code UEDGE shows that the radiative SF divertor can successfully reduce peak divertor heat flux for the projected PSOL ≃9 MW case. In conclusion, the radiative SF divertor with carbon impurity provides a wider ne operating window, 50% less argon is needed in the impurity-seeded SF configuration to achieve similar qpeak reduction factors (cf. standard divertor).},
doi = {10.1109/SOFE.2015.7482263},
journal = {2015 IEEE 26th Symposium on Fusion Engineering (SOFE)},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {6}
}