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Title: Performance and properties of the first plasmas of Wendelstein 7-X

The optimized, superconducting stellarator Wendelstein 7-X went into operation and delivered first measurement data after 15 years of construction and one year commissioning. Errors in the magnet assembly were confirmend to be small. Plasma operation was started with 5 MW electron cyclotron resonance heating (ECRH) power and five inboard limiters. Core plasma values of $${{T}_{\text{e}}}>8$$ keV, $${{T}_{\text{i}}}>2$$ keV at line-integrated densities $$n\approx 3\centerdot {{10}^{19}}~{{\text{m}}^{-2}}$$ were achieved, exceeding the original expectations by about a factor of two. Indications for a core-electron-root were found. The energy confinement times are in line with the international stellarator scaling, despite unfavourable wall conditions, i.e. large areas of metal surfaces and particle sources from the limiter close to the plasma volume. Well controlled shorter hydrogen discharges at higher power (4 MW ECRH power for 1 s) and longer discharges at lower power (0.7 MW ECRH power for 6 s) could be routinely established after proper wall conditioning. Lastly, the fairly large set of diagnostic systems running in the end of the 10 weeks operation campaign provided first insights into expected and unexpected physics of optimized stellarators.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [4] ;  [1] ;  [5] ;  [6] ;  [1] ;  [1] ;  [1] ;  [5] more »;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [7] ;  [2] ;  [8] ;  [1] ;  [1] « less
  1. Max-Planck Institute for Plasma Physics, Greifswald (Germany)
  2. CIEMAT, Madrid (Spain)
  3. Wigner Research Center for Physics, Budapest (Hungary)
  4. Research Center Julich, Julich (Germany)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  6. Univ. of Maryland, College Park, MD (United States)
  7. Auburn Univ., Auburn, AL (United States)
  8. LPP-ERM/KMS, Brussels (Belgium)
Publication Date:
Grant/Contract Number:
633053
Type:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 1; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE
Contributing Orgs:
The Wendelstein 7-X Team
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; stellarator; optimization; plasma performance; central electron root
OSTI Identifier:
1335689

Klinger, Thomas, Alonso, A., Bozhenkov, S., Burhenn, R., Dinklage, A., Fuchert, G., Geiger, J., Grulke, O., Langenberg, A., Hirsch, M., Kocsis, G., Knauer, J., Krämer-Flecken, A., Laqua, H., Lazerson, S., Landreman, M., Maaßberg, H., Marsen, S., Otte, M., Pablant, N., Pasch, E., Rahbarnia, K., Stange, T., Szepesi, T., Thomsen, H., Traverso, P., Velasco, J. L., Wauters, T., Weir, G., and Windisch, T.. Performance and properties of the first plasmas of Wendelstein 7-X. United States: N. p., Web. doi:10.1088/0741-3335/59/1/014018.
Klinger, Thomas, Alonso, A., Bozhenkov, S., Burhenn, R., Dinklage, A., Fuchert, G., Geiger, J., Grulke, O., Langenberg, A., Hirsch, M., Kocsis, G., Knauer, J., Krämer-Flecken, A., Laqua, H., Lazerson, S., Landreman, M., Maaßberg, H., Marsen, S., Otte, M., Pablant, N., Pasch, E., Rahbarnia, K., Stange, T., Szepesi, T., Thomsen, H., Traverso, P., Velasco, J. L., Wauters, T., Weir, G., & Windisch, T.. Performance and properties of the first plasmas of Wendelstein 7-X. United States. doi:10.1088/0741-3335/59/1/014018.
Klinger, Thomas, Alonso, A., Bozhenkov, S., Burhenn, R., Dinklage, A., Fuchert, G., Geiger, J., Grulke, O., Langenberg, A., Hirsch, M., Kocsis, G., Knauer, J., Krämer-Flecken, A., Laqua, H., Lazerson, S., Landreman, M., Maaßberg, H., Marsen, S., Otte, M., Pablant, N., Pasch, E., Rahbarnia, K., Stange, T., Szepesi, T., Thomsen, H., Traverso, P., Velasco, J. L., Wauters, T., Weir, G., and Windisch, T.. 2016. "Performance and properties of the first plasmas of Wendelstein 7-X". United States. doi:10.1088/0741-3335/59/1/014018. https://www.osti.gov/servlets/purl/1335689.
@article{osti_1335689,
title = {Performance and properties of the first plasmas of Wendelstein 7-X},
author = {Klinger, Thomas and Alonso, A. and Bozhenkov, S. and Burhenn, R. and Dinklage, A. and Fuchert, G. and Geiger, J. and Grulke, O. and Langenberg, A. and Hirsch, M. and Kocsis, G. and Knauer, J. and Krämer-Flecken, A. and Laqua, H. and Lazerson, S. and Landreman, M. and Maaßberg, H. and Marsen, S. and Otte, M. and Pablant, N. and Pasch, E. and Rahbarnia, K. and Stange, T. and Szepesi, T. and Thomsen, H. and Traverso, P. and Velasco, J. L. and Wauters, T. and Weir, G. and Windisch, T.},
abstractNote = {The optimized, superconducting stellarator Wendelstein 7-X went into operation and delivered first measurement data after 15 years of construction and one year commissioning. Errors in the magnet assembly were confirmend to be small. Plasma operation was started with 5 MW electron cyclotron resonance heating (ECRH) power and five inboard limiters. Core plasma values of ${{T}_{\text{e}}}>8$ keV, ${{T}_{\text{i}}}>2$ keV at line-integrated densities $n\approx 3\centerdot {{10}^{19}}~{{\text{m}}^{-2}}$ were achieved, exceeding the original expectations by about a factor of two. Indications for a core-electron-root were found. The energy confinement times are in line with the international stellarator scaling, despite unfavourable wall conditions, i.e. large areas of metal surfaces and particle sources from the limiter close to the plasma volume. Well controlled shorter hydrogen discharges at higher power (4 MW ECRH power for 1 s) and longer discharges at lower power (0.7 MW ECRH power for 6 s) could be routinely established after proper wall conditioning. Lastly, the fairly large set of diagnostic systems running in the end of the 10 weeks operation campaign provided first insights into expected and unexpected physics of optimized stellarators.},
doi = {10.1088/0741-3335/59/1/014018},
journal = {Plasma Physics and Controlled Fusion},
number = 1,
volume = 59,
place = {United States},
year = {2016},
month = {10}
}