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Title: Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1];  [1];  [2];
  1. Max Planck Institute for Plasma Physics, Greifswald, Germany
  2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1361899
Grant/Contract Number:
SC0014210
Resource Type:
Journal Article: Published Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Related Information: CHORUS Timestamp: 2017-06-08 13:09:29; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Sunn Pedersen, Thomas, Dinklage, Andreas, Turkin, Yuriy, Wolf, Robert, Bozhenkov, Sergey, Geiger, Joachim, Fuchert, Golo, Bosch, Hans-Stephan, Rahbarnia, Kian, Thomsen, Henning, Neuner, Ulrich, Klinger, Thomas, Langenberg, Andreas, Trimiño Mora, Humberto, Kornejew, Petra, Knauer, Jens, Hirsch, Matthias, Pablant, Novimir, and the W7-X Team. Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X. United States: N. p., 2017. Web. doi:10.1063/1.4983629.
Sunn Pedersen, Thomas, Dinklage, Andreas, Turkin, Yuriy, Wolf, Robert, Bozhenkov, Sergey, Geiger, Joachim, Fuchert, Golo, Bosch, Hans-Stephan, Rahbarnia, Kian, Thomsen, Henning, Neuner, Ulrich, Klinger, Thomas, Langenberg, Andreas, Trimiño Mora, Humberto, Kornejew, Petra, Knauer, Jens, Hirsch, Matthias, Pablant, Novimir, & the W7-X Team. Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X. United States. doi:10.1063/1.4983629.
Sunn Pedersen, Thomas, Dinklage, Andreas, Turkin, Yuriy, Wolf, Robert, Bozhenkov, Sergey, Geiger, Joachim, Fuchert, Golo, Bosch, Hans-Stephan, Rahbarnia, Kian, Thomsen, Henning, Neuner, Ulrich, Klinger, Thomas, Langenberg, Andreas, Trimiño Mora, Humberto, Kornejew, Petra, Knauer, Jens, Hirsch, Matthias, Pablant, Novimir, and the W7-X Team. 2017. "Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X". United States. doi:10.1063/1.4983629.
@article{osti_1361899,
title = {Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X},
author = {Sunn Pedersen, Thomas and Dinklage, Andreas and Turkin, Yuriy and Wolf, Robert and Bozhenkov, Sergey and Geiger, Joachim and Fuchert, Golo and Bosch, Hans-Stephan and Rahbarnia, Kian and Thomsen, Henning and Neuner, Ulrich and Klinger, Thomas and Langenberg, Andreas and Trimiño Mora, Humberto and Kornejew, Petra and Knauer, Jens and Hirsch, Matthias and Pablant, Novimir and the W7-X Team},
abstractNote = {},
doi = {10.1063/1.4983629},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = 2017,
month = 5
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4983629

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

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  • Cited by 2
  • Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered amore » MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. Finally, an overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.« less
  • Here, after completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreedmore » for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 × 10 19 m –3, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.« less
  • An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infrared (IR) optical diagnostics are described.