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Direct measurement of divertor exhaust neo enrichment in DIII-D

Conference ·
OSTI ID:383042
;  [1];  [2];  [3]; ;  [4]; ;  [5]
  1. Oak Ridge National Lab., TN (United States)
  2. Oak Ridge Associated Universities, Inc., TN (United States)
  3. Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee
  4. Institut National de la Recherche Scientifique, Varennes, PQ (Canada)
  5. Lawrence Livermore National Lab., CA (United States)
We report first direct measurements of divertor exhaust gas impurity enrichment, {eta}{sub exh}=(exhaust impurity concentration){divided_by}(core impurity concentration), for both unpumped and D{sub 2} puff-with-divertor-pump conditions. The experiment was performed with neutral beam heated, ELMing H-mode, single-null diverted deuterium plasmas with matched core and exhaust parameters in the DIII-D tokamak. Neon gas impurity was puffed into the divertor. Neon density was measured in the exhaust by a specially modified Penning gauge and in the core by absolute charge exchange recombination spectroscopy. Neon particle accounting indicates that much of the puffed neon entered a temporary unmeasured reservoir, inferred to be the graphite divertor target, which makes direct measurements necessary to calculate divertor enrichments. D{sub 2} puff into the SOL (scrape-off layer) with pumping increased {eta}{sub exh} threefold over either unpumped conditions or D{sub 2} puff directly into the divertor with pumping. These results show that SOL flow plays an important role in divertor exhaust impurity enrichment.
Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC03-89ER51114; AC05-96OR22464; W-7405-ENG-48
OSTI ID:
383042
Report Number(s):
GA--A22343; CONF-960569--12; ON: DE97000111
Country of Publication:
United States
Language:
English

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