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Title: Interpretations of the impact of cross-field drifts on divertor flows in DIII-D with UEDGE

Simulations using the multi-fluid code UEDGE indicates that, in low confinement (Lmode) plasmas in DIII-D, recycling driven flows dominate poloidal particle flows in the divertor, whereas E×B drift flows dominate the radial particle flows. In contrast, in high confinement (H-mode) conditions E×B drift flows dominate both poloidal and radial particle flows in the divertor. UEDGE indicates that the toroidal C 2+ flow velocities in the divertor plasma are entrained within 30% to the background deuterium flow in both Land H-mode plasmas in the plasma region where the CIII 465 nm emission is measured. Therefore, UEDGE indicates that the Carbon Doppler Coherence Imaging System (CIS), measuring the toroidal velocity of the C 2+ ions, can provide insight to the deuterium flows in the divertor. Parallel-to-B velocity dominates the toroidal divertor flow; direct drift impact being less than 1%. Toroidal divertor flow is predicted to reverse when the magnetic field is reversed. This is explained by the parallel-B flow towards the nearest divertor plate corresponding to opposite toroidal directions in opposite toroidal field configurations. Due to strong poloidal E×B flows in H-mode, net poloidal particle transport can be in opposite direction than the poloidal component of the parallel-B plasma flow.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [3] ;  [1] ;  [4] ;  [4] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Aalto Univ., Aalto (Finland)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. General Atomics, San Diego, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-696759
Journal ID: ISSN 2352-1791; PII: S2352179116302447
Grant/Contract Number:
FC02-04ER54698; AC52-07NA27344; FG02-07ER54917; AC05-00OR22725; AC04-94AL85000
Type:
Published Article
Journal Name:
Nuclear Materials and Energy
Additional Journal Information:
Journal Volume: 12; Journal ID: ISSN 2352-1791
Publisher:
Elsevier
Research Org:
General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1341465
Alternate Identifier(s):
OSTI ID: 1372468; OSTI ID: 1410042