Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited)

J. Ren; D. C. Donovan; J. G. Watkins; H. Q. Wang; C. Lasnier; T. Looby; J. Canik; D. Rudakov; P. C. Stangeby; D. Thomas; R. Boivin

doi:10.1063/5.0101719

Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited)

J. Ren, D. C. Donovan, J. G. Watkins, H. Q. Wang, C. Lasnier, T. Looby, J. Canik, D. Rudakov, P. C. Stangeby, D. Thomas, R. Boivin

Fusion Energy Division

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

1 Scopus citations

Abstract

The Surface Eroding Thermocouple (SETC) is a robust diagnostic utilized in DIII-D to provide fast, edge-localized modes (ELMs) resolved heat flux measurements, in particular in geometric regions that are too shadowed for traditional infrared thermography. In order to further investigate the power dissipation in the divertor region, a combination of flush-mounted and recessed SETCs was developed to assess the effect on surface heating from non-charged particles at the divertor target. Utilizing the Divertor Materials Evaluation System sample exposure platform, the first demonstration of the feasibility of using this new method to distinguish between the heat flux from charged particles and that from neutrals and radiative heating was achieved. This paper details the process of using the combination of flush SETCs and recessed SETCs to measure the multiple heat flux components at the divertor target and further discusses how to determine two important ratios, α (ratio of heat flux from charged particles deposit on recessed SETC to that deposit on flush SETC) and β (ratio of heat flux from non-charged particles deposit on recessed SETC to that deposit on flush SETC), in the estimation of the heat flux from non-charged particle sources. Using a time dependent ratio α, it was found that ∼50% of the total incident heat flux is attributable to the non-charged particles in the fully detached open divertor in DIII-D. Finally, the new application of similar SETC diagnostics in the Small Angle Slot divertor with a V-like configuration and partial tungsten coated surface (SAS-VW) is also introduced.

Original language	English
Article number	103541
Journal	Review of Scientific Instruments
Volume	93
Issue number	10
DOIs	https://doi.org/10.1063/5.0101719
State	Published - Oct 1 2022

Funding

This work was supported by the U.S. Department of Energy DOE under Contract Nos. DE-FC02-04ER54698, DE-SC0016318, DE-SC0019256, and ED-NA0003525.

Funders	Funder number
U.S. Department of Energy	DE-SC0016318, DE-SC0019256, ED-NA0003525, DE-FC02-04ER54698

UN SDGs

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

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10.1063/5.0101719

Cite this

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title = "Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited)",

abstract = "The Surface Eroding Thermocouple (SETC) is a robust diagnostic utilized in DIII-D to provide fast, edge-localized modes (ELMs) resolved heat flux measurements, in particular in geometric regions that are too shadowed for traditional infrared thermography. In order to further investigate the power dissipation in the divertor region, a combination of flush-mounted and recessed SETCs was developed to assess the effect on surface heating from non-charged particles at the divertor target. Utilizing the Divertor Materials Evaluation System sample exposure platform, the first demonstration of the feasibility of using this new method to distinguish between the heat flux from charged particles and that from neutrals and radiative heating was achieved. This paper details the process of using the combination of flush SETCs and recessed SETCs to measure the multiple heat flux components at the divertor target and further discusses how to determine two important ratios, α (ratio of heat flux from charged particles deposit on recessed SETC to that deposit on flush SETC) and β (ratio of heat flux from non-charged particles deposit on recessed SETC to that deposit on flush SETC), in the estimation of the heat flux from non-charged particle sources. Using a time dependent ratio α, it was found that ∼50% of the total incident heat flux is attributable to the non-charged particles in the fully detached open divertor in DIII-D. Finally, the new application of similar SETC diagnostics in the Small Angle Slot divertor with a V-like configuration and partial tungsten coated surface (SAS-VW) is also introduced.",

author = "J. Ren and Donovan, {D. C.} and Watkins, {J. G.} and Wang, {H. Q.} and C. Lasnier and T. Looby and J. Canik and D. Rudakov and Stangeby, {P. C.} and D. Thomas and R. Boivin",

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AU - Ren, J.

AU - Donovan, D. C.

AU - Watkins, J. G.

AU - Wang, H. Q.

AU - Lasnier, C.

AU - Looby, T.

AU - Canik, J.

AU - Rudakov, D.

AU - Stangeby, P. C.

AU - Thomas, D.

AU - Boivin, R.

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AB - The Surface Eroding Thermocouple (SETC) is a robust diagnostic utilized in DIII-D to provide fast, edge-localized modes (ELMs) resolved heat flux measurements, in particular in geometric regions that are too shadowed for traditional infrared thermography. In order to further investigate the power dissipation in the divertor region, a combination of flush-mounted and recessed SETCs was developed to assess the effect on surface heating from non-charged particles at the divertor target. Utilizing the Divertor Materials Evaluation System sample exposure platform, the first demonstration of the feasibility of using this new method to distinguish between the heat flux from charged particles and that from neutrals and radiative heating was achieved. This paper details the process of using the combination of flush SETCs and recessed SETCs to measure the multiple heat flux components at the divertor target and further discusses how to determine two important ratios, α (ratio of heat flux from charged particles deposit on recessed SETC to that deposit on flush SETC) and β (ratio of heat flux from non-charged particles deposit on recessed SETC to that deposit on flush SETC), in the estimation of the heat flux from non-charged particle sources. Using a time dependent ratio α, it was found that ∼50% of the total incident heat flux is attributable to the non-charged particles in the fully detached open divertor in DIII-D. Finally, the new application of similar SETC diagnostics in the Small Angle Slot divertor with a V-like configuration and partial tungsten coated surface (SAS-VW) is also introduced.

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Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited)

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