Error field measurement, correction and heat flux balancing on Wendelstein 7-X

Lazerson, Samuel A.; Otte, Matthias; Jakubowski, Marcin; Israeli, Ben; Wurden, Glen A.; Wenzel, Uwe; Andreeva, Tamara; Bozhenkov, Sergey; Biedermann, Christoph; Kocsis, Gábor; Szepesi, Tamás; Geiger, Joachim; Pedersen, Thomas Sunn; Gates, David

doi:10.1088/1741-4326/aa60e7

Error field measurement, correction and heat flux balancing on Wendelstein 7-X

Journal Article · Fri Mar 10 00:00:00 EST 2017 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aa60e7· OSTI ID:1353402

^[1]; Otte, Matthias ^[2]; Jakubowski, Marcin ^[2]; Israeli, Ben ^[3]; Wurden, Glen A. ^[4]; Wenzel, Uwe ^[2]; Andreeva, Tamara ^[2]; Bozhenkov, Sergey ^[2]; Biedermann, Christoph ^[2]; Kocsis, Gábor ^[5]; Szepesi, Tamás ^[5]; Geiger, Joachim ^[2]; Pedersen, Thomas Sunn ^[2]; ^[1]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Max Planck Inst. for Plasma Physics, Greifswald (Germany)
Columbia Univ., New York, NY (United States)
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Wigner Research Center for Physics, Budapest (Hungary)

The measurement and correction of error fields in Wendelstein 7-X (W7-X) is critical to long pulse high beta operation, as small error fields may cause overloading of divertor plates in some configurations. Accordingly, as part of a broad collaborative effort, the detection and correction of error fields on the W7-X experiment has been performed using the trim coil system in conjunction with the flux surface mapping diagnostic and high resolution infrared camera. In the early commissioning phase of the experiment, the trim coils were used to open an n/m = 1/2 island chain in a specially designed magnetic configuration. The flux surfacing mapping diagnostic was then able to directly image the magnetic topology of the experiment, allowing the inference of a small similar to 4 cm intrinsic island chain. The suspected main sources of the error field, slight misalignment and deformations of the superconducting coils, are then confirmed through experimental modeling using the detailed measurements of the coil positions. Observations of the limiters temperatures in module 5 shows a clear dependence of the limiter heat flux pattern as the perturbing fields are rotated. Plasma experiments without applied correcting fields show a significant asymmetry in neutral pressure (centered in module 4) and light emission (visible, H-alpha, CII, and CIII). Such pressure asymmetry is associated with plasma-wall (limiter) interaction asymmetries between the modules. Application of trim coil fields with n = 1 waveform correct the imbalance. Confirmation of the error fields allows the assessment of magnetic fields which resonate with the n/m = 5/5 island chain.

View Accepted Manuscript (DOE)

Research Organization:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

Contributing Organization:: The W7-X Team

Grant/Contract Number:: AC02-09CH11466; AC52-06NA25396

OSTI ID:: 1353402

Alternate ID(s):: OSTI ID: 22738526
OSTI ID: 22925647
OSTI ID: 1407875

Report Number(s):: LA-UR--16-27305; PPPL--5316

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 4 Vol. 57; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (22)

Influence of construction errors on Wendelstein 7-X magnetic configurations Andreeva, T.; Bräuer, T.; Endler, M. Fusion Engineering and Design, Vol. 84, Issue 2-6 https://doi.org/10.1016/j.fusengdes.2008.12.073	journal	June 2009
Service oriented architecture for scientific analysis at W7-X. An example of a field line tracer Bozhenkov, S. A.; Geiger, J.; Grahl, M. Fusion Engineering and Design, Vol. 88, Issue 11 https://doi.org/10.1016/j.fusengdes.2013.07.003	journal	November 2013
Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000 Pedersen, T. Sunn; Otte, M.; Lazerson, S. Nature Communications, Vol. 7, Issue 1 https://doi.org/10.1038/ncomms13493	journal	November 2016
Electron beam and magnetic field mapping techniques used to determine field errors in the ATF torsatron Colchin, R. J.; Anderson, F. S. B.; England, A. C. Review of Scientific Instruments, Vol. 60, Issue 8 https://doi.org/10.1063/1.1141082	journal	August 1989
Transport optimization in stellarators Mynick, H. E. Physics of Plasmas, Vol. 13, Issue 5 https://doi.org/10.1063/1.2177643	journal	May 2006
Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator Drewelow, Peter; Bräuer, Torsten; Otte, Matthias Review of Scientific Instruments, Vol. 80, Issue 12 https://doi.org/10.1063/1.3263820	journal	December 2009
The limits and challenges of error field correction for ITER Buttery, R. J.; Boozer, A. H.; Liu, Y. Q. Physics of Plasmas, Vol. 19, Issue 5 https://doi.org/10.1063/1.3694655	journal	May 2012
Spectroscopic imaging of limiter heat and particle fluxes and the resulting impurity sources during Wendelstein 7-X startup plasmas Stephey, L.; Wurden, G. A.; Schmitz, O. Review of Scientific Instruments, Vol. 87, Issue 11 https://doi.org/10.1063/1.4959274	journal	August 2016
A high resolution IR/visible imaging system for the W7-X limiter Wurden, G. A.; Stephey, L. A.; Biedermann, C. Review of Scientific Instruments, Vol. 87, Issue 11 https://doi.org/10.1063/1.4960596	journal	August 2016
Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X (invited) Krychowiak, M.; Adnan, A.; Alonso, A. Review of Scientific Instruments, Vol. 87, Issue 11 https://doi.org/10.1063/1.4964376	journal	October 2016
The spectral basis of optimal error field correction on DIII-D Paz-Soldan, C.; Buttery, R. J.; Garofalo, A. M. Nuclear Fusion, Vol. 54, Issue 7 https://doi.org/10.1088/0029-5515/54/7/073013	journal	April 2014
Tracking of the magnet system geometry during Wendelstein 7-X construction to achieve the designed magnetic field Andreeva, T.; Bräuer, T.; Bykov, V. Nuclear Fusion, Vol. 55, Issue 6 https://doi.org/10.1088/0029-5515/55/6/063025	journal	May 2015
First measurements of error fields on W7-X using flux surface mapping Lazerson, Samuel A.; Otte, Matthias; Bozhenkov, Sergey Nuclear Fusion, Vol. 56, Issue 10 https://doi.org/10.1088/0029-5515/56/10/106005	journal	August 2016
Methods for measuring 1/1 error field in Wendelstein 7-X stellarator Bozhenkov, S. A.; Lazerson, S.; Otte, M. Nuclear Fusion, Vol. 56, Issue 7 https://doi.org/10.1088/0029-5515/56/7/076002	journal	June 2016
Setup and initial results from the magnetic flux surface diagnostics at Wendelstein 7-X Otte, M.; Aßmus, D.; Biedermann, C. Plasma Physics and Controlled Fusion, Vol. 58, Issue 6 https://doi.org/10.1088/0741-3335/58/6/064003	journal	May 2016
Experimental and numerical study of error fields in the CNT stellarator Hammond, K. C.; Anichowski, A.; Brenner, P. W. Plasma Physics and Controlled Fusion, Vol. 58, Issue 7 https://doi.org/10.1088/0741-3335/58/7/074002	journal	May 2016
Physics of magnetically confined plasmas Boozer, Allen H. Reviews of Modern Physics, Vol. 76, Issue 4 https://doi.org/10.1103/RevModPhys.76.1071	journal	January 2005
The Trim Coils for the Wendelstein 7-X Magnet System Rummel, T.; Risse, K.; Kisslinger, J. IEEE Transactions on Applied Superconductivity, Vol. 22, Issue 3 https://doi.org/10.1109/TASC.2011.2182027	journal	June 2012
The Wendelstein 7-X Trim Coil System Rummel, Thomas; Neilson, Hutch; Risze, Konrad IEEE Transactions on Applied Superconductivity, Vol. 24, Issue 3 https://doi.org/10.1109/TASC.2013.2284671	journal	June 2014
The Superconducting Magnet System of the Stellarator Wendelstein 7-X Rummel, Thomas; Ribe, Konrad; Ehrke, Gunnar IEEE Transactions on Plasma Science, Vol. 40, Issue 3 https://doi.org/10.1109/TPS.2012.2184774	journal	March 2012
Analysis of the Magnetic Field Perturbations during the Assembly of Wendelstein 7-X Andreeva, T.; Bräuer, T.; Endler, M. Fusion Science and Technology, Vol. 46, Issue 2 https://doi.org/10.13182/FST04-A578	journal	September 2004
Flux Surface Mapping in LHD Morisaki, T.; Shoji, M.; Masuzaki, S. Fusion Science and Technology, Vol. 58, Issue 1 https://doi.org/10.13182/FST10-A10832	journal	August 2010

Cited By (7)

Mapping of the HIDRA stellarator magnetic flux surfaces Rizkallah, Rabel; Marcinko, Steven; Curreli, Davide Physics of Plasmas, Vol. 26, Issue 9 https://doi.org/10.1063/1.5100744	journal	September 2019
Hessian matrix approach for determining error field sensitivity to coil deviations Zhu, Caoxiang; Hudson, Stuart R.; Lazerson, Samuel A. Plasma Physics and Controlled Fusion, Vol. 60, Issue 5 https://doi.org/10.1088/1361-6587/aab6cb	journal	April 2018
Effect of toroidal plasma currents on the Wendelstein 7-X Scrape-Off Layer Killer, Carsten; Gao, Yu; Perseo, Valeria Plasma Physics and Controlled Fusion, Vol. 61, Issue 12 https://doi.org/10.1088/1361-6587/ab4f2d	journal	November 2019
Major results from the first plasma campaign of the Wendelstein 7-X stellarator Wolf, R. C.; Ali, A.; Alonso, A. Nuclear Fusion, Vol. 57, Issue 10 https://doi.org/10.1088/1741-4326/aa770d	journal	July 2017
Measurements and correction of the 1/1 error field in Wendelstein 7-X Bozhenkov, S. A.; Otte, M.; Biedermann, C. Nuclear Fusion, Vol. 59, Issue 2 https://doi.org/10.1088/1741-4326/aaf20c	journal	December 2018
Methods for quantitative study of divertor heat loads on W7-X Gao, Y.; Jakubowski, Marcin W.; Drewelow, Peter Nuclear Fusion, Vol. 59, Issue 6 https://doi.org/10.1088/1741-4326/ab0f49	journal	April 2019
Characterization of the W7-X scrape-off layer using reciprocating probes Killer, Carsten; Grulke, Olaf; Drews, Philipp Nuclear Fusion, Vol. 59, Issue 8 https://doi.org/10.1088/1741-4326/ab2272	journal	June 2019

Similar Records

First measurements of error fields on W7-X using flux surface mapping

Journal Article · Tue Aug 02 20:00:00 EDT 2016 · Nuclear Fusion · OSTI ID:1335163

Error fields in the Wendelstein 7-X stellarator

Journal Article · Thu Nov 08 19:00:00 EST 2018 · Plasma Physics and Controlled Fusion · OSTI ID:1484166

Measurements and correction of the 1/1 error field in Wendelstein 7-X

Journal Article · Tue Dec 18 19:00:00 EST 2018 · Nuclear Fusion · OSTI ID:1512870

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Error fields
Limiter
Magnetic Fusion Energy
Magnetic-field
Stellarator
W7-X
Wendelstein 7-X
stellarator
error fields
trim coils
heat flux

Error field measurement, correction and heat flux balancing on Wendelstein 7-X

Citation Formats

References (22)

Cited By (7)

Similar Records

Related Subjects