First measurements of error fields on W7-X using flux surface mapping
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Max-Planck-Institut fur Plasmaphysik, Greifswald (Germany)
Error fields have been detected and quantified using the flux surface mapping diagnostic system on Wendelstein 7-X (W7-X). A low-field '$${\rlap{-}\ \iota} =1/2$$ ' magnetic configuration ($${\rlap{-}\ \iota} =\iota /2\pi $$ ), sensitive to error fields, was developed in order to detect their presence using the flux surface mapping diagnostic. In this configuration, a vacuum flux surface with rotational transform of n/m = 1/2 is created at the mid-radius of the vacuum flux surfaces. If no error fields are present a vanishingly small n/m = 5/10 island chain should be present. Modeling indicates that if an n = 1 perturbing field is applied by the trim coils, a large n/m = 1/2 island chain will be opened. This island chain is used to create a perturbation large enough to be imaged by the diagnostic. Phase and amplitude scans of the applied field allow the measurement of a small $$\sim 0.04$$ m intrinsic island chain with a $${{130}^{\circ}}$$ phase relative to the first module of the W7-X experiment. Lastly, these error fields are determined to be small and easily correctable by the trim coil system.
- Research Organization:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Contributing Organization:
- The W7-X Team
- Grant/Contract Number:
- AC02-09CH11466
- OSTI ID:
- 1335163
- Alternate ID(s):
- OSTI ID: 1281330
- Report Number(s):
- 5233
- Journal Information:
- Nuclear Fusion, Vol. 56, Issue 10; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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