The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling

T. Abrams; R. Ding; H. Y. Guo; D. M. Thomas; C. P. Chrobak; D. L. Rudakov; A. G. McLean; E. A. Unterberg; A. R. Briesemeister; P. C. Stangeby; J. D. Elder; W. R. Wampler; J. G. Watkins

doi:10.1088/1741-4326/aa66b2

The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling

T. Abrams, R. Ding, H. Y. Guo, D. M. Thomas, C. P. Chrobak, D. L. Rudakov, A. G. McLean, E. A. Unterberg, A. R. Briesemeister, P. C. Stangeby, J. D. Elder, W. R. Wampler, J. G. Watkins

Power Exhaust and Particle Control

Research output: Contribution to journal › Article › peer-review

50 Scopus citations

Abstract

It is important to develop a predictive capability for the tungsten source rate near the strike points during H-mode operation in ITER and beyond. H-mode deuterium plasma exposures were performed on W-coated graphite and molybdenum substrates in the DIII-D divertor using DiMES. The W-I 400.9 nm spectral line was monitored by fast filtered diagnostics cross calibrated via a high-resolution spectrometer to resolve inter-ELM W erosion. The effective ionization/photon (S/XB) was calibrated using a unique method developed on DIII-D based on surface analysis. Inferred S/XB values agree with an existing empirical scaling at low electron density (n _e) but diverge at higher densities, consistent with recent ADAS atomic physics modeling results. Edge modeling of the inter-ELM phase is conducted via OEDGE utilizing the new capability for charge-state resolved carbon impurity fluxes. ERO modeling is performed with the calculated main ion and impurity plasma background from OEDGE. ERO results demonstrate the importance a mixed-material surface model in the interpretation of W sourcing measurements. It is demonstrated that measured inter-ELM W erosion rates can be well explained by C→W sputtering only if a realistic mixed material model is incorporated.

Original language	English
Article number	056034
Journal	Nuclear Fusion
Volume	57
Issue number	5
DOIs	https://doi.org/10.1088/1741-4326/aa66b2
State	Published - Apr 3 2017

Funding

This work was supported by U.S. DOE under DE-FC02-04ER54698, DE-FG02-07ER54917, DE-SC00019691, DEAC52-07NA27344, DE-AC05-00OR22725, and DE-AC04-94AL85000. This material is based upon work supported by the US Department of Energy, Office of Science, Office of Fusion Energy Sciences and Office of Advanced Scientific Computing Research through the Scientific Discovery through Advanced Computing (SciDAC) project on Plasma-Surface Interactions, under Award No. GA-DE-SC0008698.

Funders	Funder number
U.S. DOE	DE-AC05-00OR22725, DE-SC00019691, DE-AC04-94AL85000, DE-FC02-04ER54698, DE-FG02-07ER54917, DEAC52-07NA27344
US Department of Energy
Office of Science
Advanced Scientific Computing Research	GA-DE-SC0008698
Fusion Energy Sciences

Keywords

DIII-D
DiMES
ERO modeling
erosion
sputtering
tungsten

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1088/1741-4326/aa66b2

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Abrams, T., Ding, R., Guo, H. Y., Thomas, D. M., Chrobak, C. P., Rudakov, D. L., McLean, A. G., Unterberg, E. A., Briesemeister, A. R., Stangeby, P. C., Elder, J. D., Wampler, W. R., & Watkins, J. G. (2017). The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling. Nuclear Fusion, 57(5), Article 056034. https://doi.org/10.1088/1741-4326/aa66b2

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abstract = "It is important to develop a predictive capability for the tungsten source rate near the strike points during H-mode operation in ITER and beyond. H-mode deuterium plasma exposures were performed on W-coated graphite and molybdenum substrates in the DIII-D divertor using DiMES. The W-I 400.9 nm spectral line was monitored by fast filtered diagnostics cross calibrated via a high-resolution spectrometer to resolve inter-ELM W erosion. The effective ionization/photon (S/XB) was calibrated using a unique method developed on DIII-D based on surface analysis. Inferred S/XB values agree with an existing empirical scaling at low electron density (n e) but diverge at higher densities, consistent with recent ADAS atomic physics modeling results. Edge modeling of the inter-ELM phase is conducted via OEDGE utilizing the new capability for charge-state resolved carbon impurity fluxes. ERO modeling is performed with the calculated main ion and impurity plasma background from OEDGE. ERO results demonstrate the importance a mixed-material surface model in the interpretation of W sourcing measurements. It is demonstrated that measured inter-ELM W erosion rates can be well explained by C→W sputtering only if a realistic mixed material model is incorporated.",

keywords = "DIII-D, DiMES, ERO modeling, erosion, sputtering, tungsten",

author = "T. Abrams and R. Ding and Guo, {H. Y.} and Thomas, {D. M.} and Chrobak, {C. P.} and Rudakov, {D. L.} and McLean, {A. G.} and Unterberg, {E. A.} and Briesemeister, {A. R.} and Stangeby, {P. C.} and Elder, {J. D.} and Wampler, {W. R.} and Watkins, {J. G.}",

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AU - Guo, H. Y.

AU - Thomas, D. M.

AU - Chrobak, C. P.

AU - Rudakov, D. L.

AU - McLean, A. G.

AU - Unterberg, E. A.

AU - Briesemeister, A. R.

AU - Stangeby, P. C.

AU - Elder, J. D.

AU - Wampler, W. R.

AU - Watkins, J. G.

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N2 - It is important to develop a predictive capability for the tungsten source rate near the strike points during H-mode operation in ITER and beyond. H-mode deuterium plasma exposures were performed on W-coated graphite and molybdenum substrates in the DIII-D divertor using DiMES. The W-I 400.9 nm spectral line was monitored by fast filtered diagnostics cross calibrated via a high-resolution spectrometer to resolve inter-ELM W erosion. The effective ionization/photon (S/XB) was calibrated using a unique method developed on DIII-D based on surface analysis. Inferred S/XB values agree with an existing empirical scaling at low electron density (n e) but diverge at higher densities, consistent with recent ADAS atomic physics modeling results. Edge modeling of the inter-ELM phase is conducted via OEDGE utilizing the new capability for charge-state resolved carbon impurity fluxes. ERO modeling is performed with the calculated main ion and impurity plasma background from OEDGE. ERO results demonstrate the importance a mixed-material surface model in the interpretation of W sourcing measurements. It is demonstrated that measured inter-ELM W erosion rates can be well explained by C→W sputtering only if a realistic mixed material model is incorporated.

AB - It is important to develop a predictive capability for the tungsten source rate near the strike points during H-mode operation in ITER and beyond. H-mode deuterium plasma exposures were performed on W-coated graphite and molybdenum substrates in the DIII-D divertor using DiMES. The W-I 400.9 nm spectral line was monitored by fast filtered diagnostics cross calibrated via a high-resolution spectrometer to resolve inter-ELM W erosion. The effective ionization/photon (S/XB) was calibrated using a unique method developed on DIII-D based on surface analysis. Inferred S/XB values agree with an existing empirical scaling at low electron density (n e) but diverge at higher densities, consistent with recent ADAS atomic physics modeling results. Edge modeling of the inter-ELM phase is conducted via OEDGE utilizing the new capability for charge-state resolved carbon impurity fluxes. ERO modeling is performed with the calculated main ion and impurity plasma background from OEDGE. ERO results demonstrate the importance a mixed-material surface model in the interpretation of W sourcing measurements. It is demonstrated that measured inter-ELM W erosion rates can be well explained by C→W sputtering only if a realistic mixed material model is incorporated.

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KW - DiMES

KW - ERO modeling

KW - erosion

KW - sputtering

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The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling

Abstract

Funding

Keywords

UN SDGs

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