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Title: Experimental verification of ion impact angle distribution at divertor surfaces using micro-engineered targets on DiMES at DIII-D

Abstract

We report the first detailed experimental verification of the polar deuterium ion impact angle distribution (IAD) on the DIII-D divertor surface in L-mode plasmas using micro-engineered trenches in samples mounted on the DiMES probe. These trenches were fabricated via focused ion beam (FIB) milling of a silicon surface partially coated with aluminum. The sample surfaces were exposed to eight repeat L-mode deuterium discharges (30 s total exposure time). The samples were examined by scanning electron microscopy (SEM), which revealed changes on the trench floor due to material deposition and evidence for shadowing of the incident deuterium ions by the trench walls. The areal distribution of carbon and aluminum deposition was measured by energy-dispersive X-ray spectroscopy (EDS). One-dimensional profiles of this deposition are in agreement with net erosion profiles calculated from a Monte Carlo micro-patterning and roughness (MPR) code for ion sputtering using as input the polar and azimuthal deuterium IADs reported previously. The deposition profiles verified the characteristic shape of the polar IADs, which have a broad maximum from 79° to 86°, over the experimental range of 68°–83°, where 0° is the surface normal direction.

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Fusion Energy Sciences (FES); National Science Foundation (NSF)
Contributing Org.:
PCCM; Materials Research Science and Engineering Center, Harvard University
OSTI Identifier:
1772145
Alternate Identifier(s):
OSTI ID: 1778097; OSTI ID: 1779681; OSTI ID: 1877321
Report Number(s):
LLNL-JRNL-836403
Journal ID: ISSN 2352-1791; S235217912100051X; 100965; PII: S235217912100051X
Grant/Contract Number:  
SC0019308; AC02-09CH11466; FC02-04ER54698; AC52-07NA27344
Resource Type:
Published Article
Journal Name:
Nuclear Materials and Energy
Additional Journal Information:
Journal Name: Nuclear Materials and Energy Journal Volume: 27 Journal Issue: C; Journal ID: ISSN 2352-1791
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Divertor; Sheath; Ion impact angle; Erosion; Deposition; DiMES; Plasma-material interaction; Surface analysis

Citation Formats

Abe, S., Skinner, C. H., Bykov, I., Yeh, Y. W., Lasa, A., Coburn, J., Rudakov, D. L., Lasnier, C. J., Wang, H. Q., McLean, A. G., Abrams, T., and Koel, B. E. Experimental verification of ion impact angle distribution at divertor surfaces using micro-engineered targets on DiMES at DIII-D. Netherlands: N. p., 2021. Web. doi:10.1016/j.nme.2021.100965.
Abe, S., Skinner, C. H., Bykov, I., Yeh, Y. W., Lasa, A., Coburn, J., Rudakov, D. L., Lasnier, C. J., Wang, H. Q., McLean, A. G., Abrams, T., & Koel, B. E. Experimental verification of ion impact angle distribution at divertor surfaces using micro-engineered targets on DiMES at DIII-D. Netherlands. https://doi.org/10.1016/j.nme.2021.100965
Abe, S., Skinner, C. H., Bykov, I., Yeh, Y. W., Lasa, A., Coburn, J., Rudakov, D. L., Lasnier, C. J., Wang, H. Q., McLean, A. G., Abrams, T., and Koel, B. E. Tue . "Experimental verification of ion impact angle distribution at divertor surfaces using micro-engineered targets on DiMES at DIII-D". Netherlands. https://doi.org/10.1016/j.nme.2021.100965.
@article{osti_1772145,
title = {Experimental verification of ion impact angle distribution at divertor surfaces using micro-engineered targets on DiMES at DIII-D},
author = {Abe, S. and Skinner, C. H. and Bykov, I. and Yeh, Y. W. and Lasa, A. and Coburn, J. and Rudakov, D. L. and Lasnier, C. J. and Wang, H. Q. and McLean, A. G. and Abrams, T. and Koel, B. E.},
abstractNote = {We report the first detailed experimental verification of the polar deuterium ion impact angle distribution (IAD) on the DIII-D divertor surface in L-mode plasmas using micro-engineered trenches in samples mounted on the DiMES probe. These trenches were fabricated via focused ion beam (FIB) milling of a silicon surface partially coated with aluminum. The sample surfaces were exposed to eight repeat L-mode deuterium discharges (30 s total exposure time). The samples were examined by scanning electron microscopy (SEM), which revealed changes on the trench floor due to material deposition and evidence for shadowing of the incident deuterium ions by the trench walls. The areal distribution of carbon and aluminum deposition was measured by energy-dispersive X-ray spectroscopy (EDS). One-dimensional profiles of this deposition are in agreement with net erosion profiles calculated from a Monte Carlo micro-patterning and roughness (MPR) code for ion sputtering using as input the polar and azimuthal deuterium IADs reported previously. The deposition profiles verified the characteristic shape of the polar IADs, which have a broad maximum from 79° to 86°, over the experimental range of 68°–83°, where 0° is the surface normal direction.},
doi = {10.1016/j.nme.2021.100965},
journal = {Nuclear Materials and Energy},
number = C,
volume = 27,
place = {Netherlands},
year = {Tue Jun 01 00:00:00 EDT 2021},
month = {Tue Jun 01 00:00:00 EDT 2021}
}

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