Investigating the effect of BT direction on W source-to-core pathways during the SAS-VW campaign on DIII-D

J. D. Mateja; S. A. Zamperini; T. Odstrcil; J. H. Nichols; T. E. Ray; A. Cacheris; T. Abrams; A. G. McLean; G. Sinclair; S. H. Messer; R. Maurizio; D. M. Thomas; D. C. Donovan

doi:10.1016/j.nme.2024.101752

Investigating the effect of B_T direction on W source-to-core pathways during the SAS-VW campaign on DIII-D

J. D. Mateja
, S. A. Zamperini
, T. Odstrcil
, J. H. Nichols
, T. E. Ray
, A. Cacheris
, T. Abrams
, A. G. McLean
, G. Sinclair
, S. H. Messer
, R. Maurizio
, D. M. Thomas
, D. C. Donovan

Power Exhaust and Particle Control

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

1 Scopus citations

Abstract

Experiments using the V-shaped closed slot tungsten (W) coated SAS-VW divertor in DIII-D studied the effects of the B_T direction on core contamination of eroded tungsten from a closed slot divertor configuration. Core W content is inferred using soft-X ray tomography (SXR) and vacuum ultraviolet spectroscopy (SPRED), while W divertor erosion is inferred from visible spectroscopy of W emission (400.9 nm) measured by in-slot filterscopes (filtered photo-multipliers). Post-mortem analysis from the campaign discovered tile misalignment leading to suspected pronounced leading-edge erosion in the unfavorable B_T direction (ion B→×∇B→ drift away from divertor) likely not captured by diagnostics. However, empirical findings show up to ∼ 2-3x larger core contamination in the favorable B_T direction even considering no additional W erosion from leading edges. A “source-to-core efficiency factor” is derived to estimate the effects of leading-edge erosion and compare W contamination for two pairs of H-mode discharges in opposite B_T directions. While having differing absolute parameters, similar core impurity density gradients suggest comparable core impurity transport. These results show that favorable B_T may have stronger source-to-core pathways for W impurities sourced from the outer divertor region. Possible explanations could include the effects of E→×B→ drifts on W transport in the scrape-off-layer (SOL) as well as previously determined fast SOL inner target directed flows in favorable B_T.

Original language	English
Article number	101752
Journal	Nuclear Materials and Energy
Volume	41
DOIs	https://doi.org/10.1016/j.nme.2024.101752
State	Published - Dec 2024

Funding

This material is based upon work supported by the U.S. Department of Energy , Office of Science , Office of Fusion Energy Sciences , using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-SC0019256 , DE-SC0023378 , DE-FC02-04ER54698 , DE-AC05-00OR22725 , DE-AC52-07NA27344 . Thank you to Bob Wilcox and Jeffrey Herfindal for their work calibrating the filterscope and MDS diagnostics. Also thank you to Tom Osborne for the SAS-V strike point location tool. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-SC0019256, DE-SC0023378, DE-FC02-04ER54698, DE-AC05-00OR22725, DE-AC52-07NA27344. Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Access to Document

10.1016/j.nme.2024.101752

Cite this

Mateja, J. D., Zamperini, S. A., Odstrcil, T., Nichols, J. H., Ray, T. E., Cacheris, A., Abrams, T., McLean, A. G., Sinclair, G., Messer, S. H., Maurizio, R., Thomas, D. M., & Donovan, D. C. (2024). Investigating the effect of B_T direction on W source-to-core pathways during the SAS-VW campaign on DIII-D. Nuclear Materials and Energy, 41, Article 101752. https://doi.org/10.1016/j.nme.2024.101752

@article{42973a2267284a0f97e94b4636e3aac1,

title = "Investigating the effect of BT direction on W source-to-core pathways during the SAS-VW campaign on DIII-D",

abstract = "Experiments using the V-shaped closed slot tungsten (W) coated SAS-VW divertor in DIII-D studied the effects of the BT direction on core contamination of eroded tungsten from a closed slot divertor configuration. Core W content is inferred using soft-X ray tomography (SXR) and vacuum ultraviolet spectroscopy (SPRED), while W divertor erosion is inferred from visible spectroscopy of W emission (400.9 nm) measured by in-slot filterscopes (filtered photo-multipliers). Post-mortem analysis from the campaign discovered tile misalignment leading to suspected pronounced leading-edge erosion in the unfavorable BT direction (ion B→×∇B→ drift away from divertor) likely not captured by diagnostics. However, empirical findings show up to ∼ 2-3x larger core contamination in the favorable BT direction even considering no additional W erosion from leading edges. A “source-to-core efficiency factor” is derived to estimate the effects of leading-edge erosion and compare W contamination for two pairs of H-mode discharges in opposite BT directions. While having differing absolute parameters, similar core impurity density gradients suggest comparable core impurity transport. These results show that favorable BT may have stronger source-to-core pathways for W impurities sourced from the outer divertor region. Possible explanations could include the effects of E→×B→ drifts on W transport in the scrape-off-layer (SOL) as well as previously determined fast SOL inner target directed flows in favorable BT.",

author = "Mateja, \{J. D.\} and Zamperini, \{S. A.\} and T. Odstrcil and Nichols, \{J. H.\} and Ray, \{T. E.\} and A. Cacheris and T. Abrams and McLean, \{A. G.\} and G. Sinclair and Messer, \{S. H.\} and R. Maurizio and Thomas, \{D. M.\} and Donovan, \{D. C.\}",

note = "Publisher Copyright: {\textcopyright} 2024",

year = "2024",

month = dec,

doi = "10.1016/j.nme.2024.101752",

language = "English",

volume = "41",

journal = "Nuclear Materials and Energy",

issn = "2352-1791",

publisher = "Elsevier",

}

TY - JOUR

T1 - Investigating the effect of BT direction on W source-to-core pathways during the SAS-VW campaign on DIII-D

AU - Mateja, J. D.

AU - Zamperini, S. A.

AU - Odstrcil, T.

AU - Nichols, J. H.

AU - Ray, T. E.

AU - Cacheris, A.

AU - Abrams, T.

AU - McLean, A. G.

AU - Sinclair, G.

AU - Messer, S. H.

AU - Maurizio, R.

AU - Thomas, D. M.

AU - Donovan, D. C.

PY - 2024/12

Y1 - 2024/12

N2 - Experiments using the V-shaped closed slot tungsten (W) coated SAS-VW divertor in DIII-D studied the effects of the BT direction on core contamination of eroded tungsten from a closed slot divertor configuration. Core W content is inferred using soft-X ray tomography (SXR) and vacuum ultraviolet spectroscopy (SPRED), while W divertor erosion is inferred from visible spectroscopy of W emission (400.9 nm) measured by in-slot filterscopes (filtered photo-multipliers). Post-mortem analysis from the campaign discovered tile misalignment leading to suspected pronounced leading-edge erosion in the unfavorable BT direction (ion B→×∇B→ drift away from divertor) likely not captured by diagnostics. However, empirical findings show up to ∼ 2-3x larger core contamination in the favorable BT direction even considering no additional W erosion from leading edges. A “source-to-core efficiency factor” is derived to estimate the effects of leading-edge erosion and compare W contamination for two pairs of H-mode discharges in opposite BT directions. While having differing absolute parameters, similar core impurity density gradients suggest comparable core impurity transport. These results show that favorable BT may have stronger source-to-core pathways for W impurities sourced from the outer divertor region. Possible explanations could include the effects of E→×B→ drifts on W transport in the scrape-off-layer (SOL) as well as previously determined fast SOL inner target directed flows in favorable BT.

AB - Experiments using the V-shaped closed slot tungsten (W) coated SAS-VW divertor in DIII-D studied the effects of the BT direction on core contamination of eroded tungsten from a closed slot divertor configuration. Core W content is inferred using soft-X ray tomography (SXR) and vacuum ultraviolet spectroscopy (SPRED), while W divertor erosion is inferred from visible spectroscopy of W emission (400.9 nm) measured by in-slot filterscopes (filtered photo-multipliers). Post-mortem analysis from the campaign discovered tile misalignment leading to suspected pronounced leading-edge erosion in the unfavorable BT direction (ion B→×∇B→ drift away from divertor) likely not captured by diagnostics. However, empirical findings show up to ∼ 2-3x larger core contamination in the favorable BT direction even considering no additional W erosion from leading edges. A “source-to-core efficiency factor” is derived to estimate the effects of leading-edge erosion and compare W contamination for two pairs of H-mode discharges in opposite BT directions. While having differing absolute parameters, similar core impurity density gradients suggest comparable core impurity transport. These results show that favorable BT may have stronger source-to-core pathways for W impurities sourced from the outer divertor region. Possible explanations could include the effects of E→×B→ drifts on W transport in the scrape-off-layer (SOL) as well as previously determined fast SOL inner target directed flows in favorable BT.

UR - https://www.scopus.com/pages/publications/85205927054

U2 - 10.1016/j.nme.2024.101752

DO - 10.1016/j.nme.2024.101752

M3 - Article

AN - SCOPUS:85205927054

SN - 2352-1791

VL - 41

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

M1 - 101752

ER -

Investigating the effect of B_T direction on W source-to-core pathways during the SAS-VW campaign on DIII-D

Abstract

Funding

Access to Document

Other files and links

Fingerprint

Cite this