The surface eroding thermocouple for fast heat flux measurement in DIII-D

Ren, J.; Donovan, David C.; Watkins, J. G.; Wang, Huiqian; Rudakov, D. L.; Murphy, Christopher; McLean, A. G.; Lasnier, C. J.; Unterberg, Ezekial; Thomas, D. M.; Boivin, R. L.

doi:10.1063/1.5038677

Title: The surface eroding thermocouple for fast heat flux measurement in DIII-D

Journal Article · 08 October 2018 · Review of Scientific Instruments

DOI: https://doi.org/10.1063/1.5038677 · OSTI ID:1543206

Ren, J. ^[1];

^[2]; Watkins, J. G. ^[3]; Wang, Huiqian ^[4]; Rudakov, D. L. ^[5]; Murphy, Christopher ^[6]; McLean, A. G. ^[7]; Lasnier, C. J. ^[7];

^[8]; Thomas, D. M. ^[6]; Boivin, R. L. ^[6]

Univ. of Tennessee, Knoxville, TN (United States)
Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Oak Ridge Associated Univ., Oak Ridge, TN (United States)
Univ. of California, San Diego, CA (United States)
General Atomics, San Diego, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

A novel type of surface eroding thermocouple (SETC) has been tested and demonstrated in the small angle slot (SAS) divertor of DIII-D for fast local heat flux measurements. The thermojunction of the SETC is formed between two thin (10 μm) ribbons, which are filed over to create microfiber junctions. These thermocouples are able to be exposed directly to the plasma at surface temperatures exceeding 2000 °C and are capable of sub-10 ms time resolution. Before installation in SAS, the SETCs were exposed in the lower DIII-D divertor during L-mode and H-mode discharges, from which results are presented. In preliminary tests, SETCs proved to be a qualified diagnostic to accurately measure both the intra-edge localized mode (ELM) and inter-ELM heat flux during H-mode shots with high frequency ELMs (hundreds of Hz) and to resolve heat flux profiles during strike point sweeps. The heat fluxes measured by using SETCs are consistent with the heat fluxes measured by using IR cameras and Langmuir probes. These new diagnostic capabilities will complement the existing IR camera measurements and will be of particularly significant value to measure surface heat flux in the SAS divertor or other regions where the IR camera lacks line of sight.

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Research Organization:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC05-00OR22725; SC0016318; FC02-04ER54698; FG02-07ER54917; NA0003525; AC52-07NA27344; SC0019256

OSTI ID:: 1543206

Alternate ID(s):: OSTI ID: 1476689; OSTI ID: 1660785

Journal Information:: Review of Scientific Instruments, Vol. 89, Issue 10; ISSN 0034-6748

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 14 works

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References (12)

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