Understanding detachment of the W7-X island divertor

Feng, Y.; Jakubowski, M.; König, R.; Krychowiak, M.; Otte, M.; Reimold, F.; Reiter, D.; Schmitz, O.; Zhang, D.; Beidler, C. D.; Biedermann, C.; Bozhenkov, S.; Brunner, K. J.; Dinklage, A.; Drewelow, P.; Effenberg, F.; Endler, M.; Fuchert, G.; Gao, Y.; Geiger, J.; Hammond, K. C.; Helander, P.; Killer, C.; Knauer, J.; Kremeyer, T.; Pasch, E.; Rudischhauser, L.; Schlisio, G.; Sunn Pedersen, T.; Wenzel, U.; Winters, V.; W7-X team,

doi:10.1088/1741-4326/ac0772

Title: Understanding detachment of the W7-X island divertor

Journal Article · Mon Jun 28 00:00:00 EDT 2021 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ac0772· OSTI ID:1814207

Feng, Y.;

; König, R.; Krychowiak, M.; Otte, M.; Reimold, F.; Reiter, D.;

; Zhang, D.;

; Biedermann, C.;

;

; Dinklage, A.;

;

; Fuchert, G.;

;

The fundamental behavior of the W7-X island divertor under detached conditions, which has been theoretically predicted with the EMC3-Eirene code, is re-examined here under the experimental conditions achieved so far and compared with the first experimental results. Both simulations and experiments cover a range of divertor configurations and plasma parameters, and show the following common trends: (1) with rising impurity radiation, the target heat load decreases 'uniformly' over the entire target surface in the sense that both the peak and average heat loads can drop by an order of magnitude. Impurity radiation (mainly from intrinsic carbon) occurs primarily at the plasma edge and the resulting negative impact on the stored energy is less than 10%. (2) When the total radiation exceeds a critical level, the target particle flux (the recycling flux Γrecy) begins to fall and can drop by a factor of 3–5 at high radiation levels without an obvious indication of significant volume recombination. (3) While Γ_recy decreases, the divertor neutral pressure continues to build up and reaches a maximum, at which point Γ_recy has declined significantly. (4) During detachment, the electron temperature at the last closed flux surface falls in a way that is not quantitatively understandable from parallel classical heat conduction processes. This paper presents a physical explanation of the numerical/experimental results described above. Furthermore, using the EMC3-Eirene code as a diagnostic tool, we are able, apparently for the first time, to provide a full quantitative analysis of each transport channel in the island divertor, aiming to clarify how the island divertor plasma self-regulates to maintain particle, energy, and momentum balance under detached conditions.

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Research Organization:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: EUROfusion Consortium; Euratom Research and Training Programme

Contributing Organization:: W7-X Team

Grant/Contract Number:: AC02-09CH11466; 633053

OSTI ID:: 1814207

Journal Information:: Nuclear Fusion, Vol. 61, Issue 8; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (44)

On the W7-X divertor performance under detached conditions Feng, Y.; Beidler, C. D.; Geiger, J. Nuclear Fusion, Vol. 56, Issue 12 https://doi.org/10.1088/0029-5515/56/12/126011	journal	September 2016
Physics of island divertors as highlighted by the example of W7-AS Feng, Y.; Sardei, F.; Grigull, P. Nuclear Fusion, Vol. 46, Issue 8 https://doi.org/10.1088/0029-5515/46/8/006	journal	July 2006
Characteristics of the divertor plasma in neutral-beam-heated ASDEX discharges Shimomura, Y.; Keilhacker, M.; Lackner, K. Nuclear Fusion, Vol. 23, Issue 7 https://doi.org/10.1088/0029-5515/23/7/002	journal	July 1983
On the compounding of certain means Lehmer, D. H. Journal of Mathematical Analysis and Applications, Vol. 36, Issue 1 https://doi.org/10.1016/0022-247x(71)90029-1	journal	October 1971
Divertor operation in stellarators: results from W7-AS and implications for future devices Grigull, P.; McCormick, K.; Renner, H. Fusion Engineering and Design, Vol. 66-68 https://doi.org/10.1016/S0920-3796(03)00121-2	journal	September 2003
The Langmuir probe system in the Wendelstein 7-X test divertor Rudischhauser, L.; Endler, M.; Höfel, U. Review of Scientific Instruments, Vol. 91, Issue 6 https://doi.org/10.1063/1.5143013	journal	June 2020
Lower hybrid penetration across a steep density gradient Cardinali, A.; Santini, F. Plasma Physics and Controlled Fusion, Vol. 53, Issue 12 https://doi.org/10.1088/0741-3335/53/12/125001	journal	October 2011
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
3D Edge Modeling and Island Divertor Physics Feng, Y.; Sardei, F.; Kisslinger, J. Contributions to Plasma Physics, Vol. 44, Issue 13 https://doi.org/10.1002/ctpp.200410009	journal	April 2004
Implicit coupling of impurity transport at the SOL–core interface Feng, Y.; Lunt, T.; Sardei, F. Computer Physics Communications, Vol. 184, Issue 6 https://doi.org/10.1016/j.cpc.2013.02.003	journal	June 2013
Screening of a high-density plasma from neutral gas penetration Lehnert, B. Nuclear Fusion, Vol. 8, Issue 3 https://doi.org/10.1088/0029-5515/8/3/005	journal	October 1968
Comparison between stellarator and tokamak divertor transport Feng, Y.; Kobayashi, M.; Lunt, T. Plasma Physics and Controlled Fusion, Vol. 53, Issue 2 https://doi.org/10.1088/0741-3335/53/2/024009	journal	January 2011
Monte-Carlo fluid approaches to detached plasmas in non-axisymmetric divertor configurations Feng, Y.; Frerichs, H.; Kobayashi, M. Plasma Physics and Controlled Fusion, Vol. 59, Issue 3 https://doi.org/10.1088/1361-6587/59/3/034006	journal	February 2017
Divertor concept for the W7-X stellarator and mode of operation Renner, H.; Boscary, J.; Greuner, H. Plasma Physics and Controlled Fusion, Vol. 44, Issue 6 https://doi.org/10.1088/0741-3335/44/6/325	journal	May 2002
Experimental divertor physics Pitcher, C. S.; Stangeby, P. C. Plasma Physics and Controlled Fusion, Vol. 39, Issue 6 https://doi.org/10.1088/0741-3335/39/6/001	journal	June 1997
Local island divertor experiments on LHD Morisaki, T.; Masuzaki, S.; Komori, A. Journal of Nuclear Materials, Vol. 337-339 https://doi.org/10.1016/j.jnucmat.2004.10.165	journal	March 2005
Disruptive tokamak density limit as scrape-off layer/divertor phenomenon Borrass, K. Nuclear Fusion, Vol. 31, Issue 6 https://doi.org/10.1088/0029-5515/31/6/003	journal	June 1991
Fluid equations for a partially ionized plasma Helander, P.; Krasheninnikov, S. I.; Catto, P. J. Physics of Plasmas, Vol. 1, Issue 10 https://doi.org/10.1063/1.870470	journal	October 1994
Density limit of tokamaks Lehnert, B. Nuclear Fusion, Vol. 23, Issue 10 https://doi.org/10.1088/0029-5515/23/10/007	journal	October 1983
The theoretical basis of a drift-optimized stellarator reactor Wobig, H. Plasma Physics and Controlled Fusion, Vol. 35, Issue 8 https://doi.org/10.1088/0741-3335/35/8/001	journal	August 1993
On the physics guidelines for a tokamak DEMO Zohm, H.; Angioni, C.; Fable, E. Nuclear Fusion, Vol. 53, Issue 7 https://doi.org/10.1088/0029-5515/53/7/073019	journal	June 2013
Experimental observation of Marfes in the W7-AS stellerator Wenzel, U.; McCormick, K.; Hildebrandt, D. Plasma Physics and Controlled Fusion, Vol. 44, Issue 10 https://doi.org/10.1088/0741-3335/44/10/103	journal	September 2002
Magnetic field structure evolution in rotating magnetic field plasmas Petrov, Yuri; Yang, Xiaokang; Huang, Tian-Sen Physics of Plasmas, Vol. 15, Issue 7 https://doi.org/10.1063/1.2952293	journal	July 2008
New Advanced Operational Regime on the W7-AS Stellarator McCormick, K.; Grigull, P.; Burhenn, R. Physical Review Letters, Vol. 89, Issue 1 https://doi.org/10.1103/PhysRevLett.89.015001	journal	June 2002
Physics in the magnetic configuration space of W7-X Geiger, J.; Beidler, C. D.; Feng, Y. Plasma Physics and Controlled Fusion, Vol. 57, Issue 1 https://doi.org/10.1088/0741-3335/57/1/014004	journal	November 2014
Basic physical processes and reduced models for plasma detachment Stangeby, P. C. Plasma Physics and Controlled Fusion, Vol. 60, Issue 4 https://doi.org/10.1088/1361-6587/aaacf6	journal	March 2018
Fluid features of the stochastic layer transport in LHD Feng, Y.; Kobayashi, M.; Morisaki, T. Nuclear Fusion, Vol. 48, Issue 2 https://doi.org/10.1088/0029-5515/48/2/024012	journal	January 2008
A simple analytic model of impurity leakage from the divertor and accumulation in the main scrape-off layer Stangeby, P. C.; Moulton, D. Nuclear Fusion, Vol. 60, Issue 10 https://doi.org/10.1088/1741-4326/ab9e16	journal	August 2020
The capabilities of steady state operation at the stellarator W7-X with emphasis on divertor design Renner, H.; Boscary, J.; Erckmann, V. Nuclear Fusion, Vol. 40, Issue 6 https://doi.org/10.1088/0029-5515/40/6/306	journal	June 2000
Island divertor experiments on the Wendelstein 7-AS stellarator McCormick, K.; Grigull, P.; Burhenn, R. Journal of Nuclear Materials, Vol. 313-316 https://doi.org/10.1016/S0022-3115(02)01506-4	journal	March 2003
First divertor physics studies in Wendelstein 7-X Sunn Pedersen, T.; König, R.; Jakubowski, M. Nuclear Fusion, Vol. 59, Issue 9 https://doi.org/10.1088/1741-4326/ab280f	journal	July 2019
Comment on “MEMS-based high speed scanning probe microscopy” [Rev. Sci. Instrum. 81, 043702 (2010)] Degertekin, F. Levent; Torun, Hamdi Review of Scientific Instruments, Vol. 81, Issue 11 https://doi.org/10.1063/1.3499232	journal	November 2010
Infrared imaging systems for wall protection in the W7-X stellarator (invited) Jakubowski, Marcin; Drewelow, Peter; Fellinger, Joris Review of Scientific Instruments, Vol. 89, Issue 10 https://doi.org/10.1063/1.5038634	journal	October 2018
Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology Perseo, V.; Effenberg, F.; Gradic, D. Nuclear Fusion, Vol. 59, Issue 12 https://doi.org/10.1088/1741-4326/ab4320	journal	September 2019
Observation of cold, high-density plasma near the Doublet III limiter Baker, D. R.; Snider, R. T.; Nagami, M. Nuclear Fusion, Vol. 22, Issue 6 https://doi.org/10.1088/0029-5515/22/6/008	journal	June 1982
Understanding baffle overloads observed in high-mirror configuration on Wendelstein 7-X Gao, Yu; Feng, Yuhe; Jakubowski, Marcin W. Nuclear Fusion, Vol. 60, Issue 9 https://doi.org/10.1088/1741-4326/ab9aff	journal	August 2020
35th European Physical Society Conference on Plasma Physics Hidalgo, Carlos Plasma Physics and Controlled Fusion, Vol. 50, Issue 12 https://doi.org/10.1088/0741-3335/50/12/120301	journal	November 2008
Error fields in the Wendelstein 7-X stellarator Lazerson, Samuel A.; Bozhenkov, Sergey; Israeli, Ben Plasma Physics and Controlled Fusion, Vol. 60, Issue 12 https://doi.org/10.1088/1361-6587/aae96b	journal	November 2018
Divertor performance on carbon and beryllium targets in JET Janeschitz, G.; König, R.; Lauro-Taroni, L. Journal of Nuclear Materials, Vol. 196-198 https://doi.org/10.1016/s0022-3115(06)80064-4	journal	December 1992
Detachment stabilization with n/m=1/1 resonant magnetic perturbation field applied to the stochastic magnetic boundary of the Large Helical Device Kobayashi, M.; Masuzaki, S.; Yamada, I. Physics of Plasmas, Vol. 17, Issue 5 https://doi.org/10.1063/1.3368681	journal	May 2010
Development of quasi-isodynamic stellarators Nührenberg, Jürgen Plasma Physics and Controlled Fusion, Vol. 52, Issue 12 https://doi.org/10.1088/0741-3335/52/12/124003	journal	November 2010
Transformation-Invariant Metamaterials Zhang, Youming; Luo, Yu; Pendry, J. B. Physical Review Letters, Vol. 123, Issue 6 https://doi.org/10.1103/physrevlett.123.067701	journal	August 2019
Radiative condensation and detachment in Wendelstein 7-AS stellarator Thomsen, H.; König, R.; Feng, Y. Nuclear Fusion, Vol. 44, Issue 8 https://doi.org/10.1088/0029-5515/44/8/002	journal	June 2004
Marfe: an edge plasma phenomenon Lipschultz, B.; LaBombard, B.; Marmar, E. S. Nuclear Fusion, Vol. 24, Issue 8 https://doi.org/10.1088/0029-5515/24/8/002	journal	August 1984

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