Plasma power recycling at the divertor surface
Abstract
With a divertor made of solid materials like carbon and tungsten, plasma ions are expected to be recycled at the divertor surface with a time-averaged particle recycling coefficient very close to unity in steady-state operation. This means that almost every plasma ion (hydrogen and helium) will be returned to the plasma, mostly as neutrals. The power flux deposited by the plasma on the divertor surface, on the other hand, can have varying recycling characteristics depending on the material choice of the divertor; the run-time atomic composition of the surface, which can be modified by material mix due to impurity migration in the chamber; and the surface morphology change over time. In general, a high-Z–material (such as tungsten) surface tends to reflect light ions and produce stronger power recycling, while a low-Z–material (such as carbon) surface tends to have a larger sticking coefficient for light ions and hence lower power recycling. Here, an explicit constraint on target plasma density and temperature is derived from the truncated bi-Maxwellian sheath model, in relation to the absorbed power load and power recycling coefficient at the divertor surface. Lastly, it is shown that because of the surface recombination energy flux, the attached plasma has amore »
- Authors:
-
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Publication Date:
- Research Org.:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC). Fusion Energy Sciences (FES) (SC-24)
- OSTI Identifier:
- 1338797
- Report Number(s):
- LA-UR-16-21594
Journal ID: ISSN 1536-1055; TRN: US1701180
- Grant/Contract Number:
- AC52-06NA25396
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Fusion Science and Technology
- Additional Journal Information:
- Journal Volume: 71; Journal Issue: 1; Journal ID: ISSN 1536-1055
- Publisher:
- American Nuclear Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Magnetic Fusion Energy
Citation Formats
Tang, Xian -Zhu, and Guo, Zehua. Plasma power recycling at the divertor surface. United States: N. p., 2016.
Web. doi:10.13182/FST16-119.
Tang, Xian -Zhu, & Guo, Zehua. Plasma power recycling at the divertor surface. United States. https://doi.org/10.13182/FST16-119
Tang, Xian -Zhu, and Guo, Zehua. Sat .
"Plasma power recycling at the divertor surface". United States. https://doi.org/10.13182/FST16-119. https://www.osti.gov/servlets/purl/1338797.
@article{osti_1338797,
title = {Plasma power recycling at the divertor surface},
author = {Tang, Xian -Zhu and Guo, Zehua},
abstractNote = {With a divertor made of solid materials like carbon and tungsten, plasma ions are expected to be recycled at the divertor surface with a time-averaged particle recycling coefficient very close to unity in steady-state operation. This means that almost every plasma ion (hydrogen and helium) will be returned to the plasma, mostly as neutrals. The power flux deposited by the plasma on the divertor surface, on the other hand, can have varying recycling characteristics depending on the material choice of the divertor; the run-time atomic composition of the surface, which can be modified by material mix due to impurity migration in the chamber; and the surface morphology change over time. In general, a high-Z–material (such as tungsten) surface tends to reflect light ions and produce stronger power recycling, while a low-Z–material (such as carbon) surface tends to have a larger sticking coefficient for light ions and hence lower power recycling. Here, an explicit constraint on target plasma density and temperature is derived from the truncated bi-Maxwellian sheath model, in relation to the absorbed power load and power recycling coefficient at the divertor surface. Lastly, it is shown that because of the surface recombination energy flux, the attached plasma has a sharper response to power recycling in comparison to a detached plasma.},
doi = {10.13182/FST16-119},
journal = {Fusion Science and Technology},
number = 1,
volume = 71,
place = {United States},
year = {Sat Dec 03 00:00:00 EST 2016},
month = {Sat Dec 03 00:00:00 EST 2016}
}
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Works referenced in this record:
Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER
journal, August 2015
- Brezinsek, S.
- Journal of Nuclear Materials, Vol. 463
Sheath energy transmission in a collisional plasma with collisionless sheath
journal, October 2015
- Tang, Xian-Zhu; Guo, Zehua
- Physics of Plasmas, Vol. 22, Issue 10
Surface modifications of W divertor components for EAST during exposure to high heat loads with He
journal, August 2015
- Li, C.; Greuner, H.; Yuan, Y.
- Journal of Nuclear Materials, Vol. 463
The snowflake divertor
journal, November 2015
- Ryutov, D. D.; Soukhanovskii, V. A.
- Physics of Plasmas, Vol. 22, Issue 11
The super X divertor (SXD) and a compact fusion neutron source (CFNS)
journal, February 2010
- Kotschenreuther, M.; Valanju, P.; Mahajan, S.
- Nuclear Fusion, Vol. 50, Issue 3
The Chodura sheath for angles of a few degrees between the magnetic field and the surface of divertor targets and limiters
journal, July 2012
- Stangeby, P. C.
- Nuclear Fusion, Vol. 52, Issue 8
Overview on plasma operation with a full tungsten wall in ASDEX Upgrade
journal, July 2013
- Neu, R.; Kallenbach, A.; Balden, M.
- Journal of Nuclear Materials, Vol. 438
High confinement/high radiated power H-mode experiments in Alcator C-Mod and consequences for International Thermonuclear Experimental Reactor (ITER) Q DT = 10 operation
journal, May 2011
- Loarte, A.; Hughes, J. W.; Reinke, M. L.
- Physics of Plasmas, Vol. 18, Issue 5
Experimental studies and modeling of complete H-mode divertor detachment in ASDEX Upgrade
journal, August 2015
- Reimold, F.; Wischmeier, M.; Bernert, M.
- Journal of Nuclear Materials, Vol. 463
Plasma sheath transmission factors for tokamak edge plasmas
journal, January 1984
- Stangeby, P. C.
- Physics of Fluids, Vol. 27, Issue 3
High density operation for reactor-relevant power exhaust
journal, August 2015
- Wischmeier, M.
- Journal of Nuclear Materials, Vol. 463
First nitrogen-seeding experiments in JET with the ITER-like Wall
journal, July 2013
- Oberkofler, M.; Douai, D.; Brezinsek, S.
- Journal of Nuclear Materials, Vol. 438
SRIM – The stopping and range of ions in matter (2010)
journal, June 2010
- Ziegler, James F.; Ziegler, M. D.; Biersack, J. P.
- Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 268, Issue 11-12
Kinetic simulations of the Chodura and Debye sheaths for magnetic fields with grazing incidence
journal, January 2016
- Coulette, David; Manfredi, Giovanni
- Plasma Physics and Controlled Fusion, Vol. 58, Issue 2
Reflection and implantation of low energy helium with tungsten surfaces
journal, April 2014
- Borovikov, Valery; Voter, Arthur F.; Tang, Xian-Zhu
- Journal of Nuclear Materials, Vol. 447, Issue 1-3
The Multi-Fluid Codes Edgeid and Edge2D: Models and Results
journal, January 1992
- Taroni, A.; Corrigan, G.; Radford, G.
- Contributions to Plasma Physics, Vol. 32, Issue 3-4
The Plasma Boundary of Magnetic Fusion Devices
book, January 2000
- Stangeby, P.
- Series in Plasma Physics
Plasma surface interactions in impurity seeded plasmas
journal, August 2011
- Kallenbach, A.; Balden, M.; Dux, R.
- Journal of Nuclear Materials, Vol. 415, Issue 1
Critical role of electron heat flux on Bohm criterion
journal, December 2016
- Tang, Xian-Zhu; Guo, Zehua
- Physics of Plasmas, Vol. 23, Issue 12
Modelling of plasma-edge and plasma–wall interaction physics at JET with the metallic first-wall
journal, February 2016
- Wiesen, S.; Groth, M.; Brezinsek, S.
- Physica Scripta, Vol. T167
Impurity seeding in ITER DT plasmas in a carbon-free environment
journal, August 2015
- Pacher, H. D.; Kukushkin, A. S.; Pacher, G. W.
- Journal of Nuclear Materials, Vol. 463
A fully implicit, time dependent 2-D fluid code for modeling tokamak edge plasmas
journal, December 1992
- Rognlien, T. D.; Milovich, J. L.; Rensink, M. E.
- Journal of Nuclear Materials, Vol. 196-198
Molecular dynamics simulation of low-energy atomic hydrogen on tungsten surface
journal, December 2010
- Yang, Zhongshi; Xu, Qian; Hong, Rongjie
- Fusion Engineering and Design, Vol. 85, Issue 7-9
Sensitivity of the Boundary Plasma to the Plasma-Material Interface
journal, January 2017
- Canik, J. M.; Tang, X. -Z.
- Fusion Science and Technology, Vol. 71, Issue 1
Plasma-material interactions in current tokamaks and their implications for next step fusion reactors
journal, December 2001
- Federici, G.; Skinner, C. H.; Brooks, J. N.
- Nuclear Fusion, Vol. 41, Issue 12
Plasma Edge Physics with B2-Eirene
journal, February 2006
- Schneider, R.; Bonnin, X.; Borrass, K.
- Contributions to Plasma Physics, Vol. 46, Issue 1-2
Investigation of He–W interactions using DiMES on DIII-D
journal, January 2016
- Doerner, R. P.; Rudakov, D. L.; Chrobak, C. P.
- Physica Scripta, Vol. T167
On the Minimum Size of DEMO
journal, October 2010
- Zohm, Hartmut
- Fusion Science and Technology, Vol. 58, Issue 2
The Plasma Boundary of Magnetic Fusion Devices
journal, January 2001
- Ghendrih, Philippe
- Plasma Physics and Controlled Fusion, Vol. 43, Issue 2
Plasma Physics and Fusion Energy
journal, November 2008
- Dolan, Thomas J.
- Fusion Science and Technology, Vol. 54, Issue 4
Plasma Physics and Fusion Energy
journal, November 2008
- Dolan, Thomas J.
- Fusion Science and Technology, Vol. 54, Issue 4