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Title: Particle transport in low-collisionality H-mode plasmas on DIII-D

In this article we show that changing from an ion temperature gradient (ITG) to trapped electron mode (TEM) dominant turbulence regime (based on linear gyrokinetic simulations) results experimentally in a strong density pump-out (defined as a reduction in line-averaged density) in low collisionality, low power H-mode plasmas. We vary the turbulence drive by changing the heating from pre-dominantly ion heatedusing neutral beam injection to electron heated using electron cyclotron heating, which changes the Te/Ti ratio and the temperature gradients. Perturbed gas puff experiments show an increase in transport outside ρ = 0.6, through a strong increase in the perturbed diffusion coefficient and a decrease in the inward pinch. Linear gyrokinetic simulations with TGLF show an increase in the particle flux outside the mid-radius. In conjunction an increase in intermediate-scale length density fluctuations is observed, which indicates an increase in turbulence intensity at typical TEM wavelengths. However, although the experimental changes in particle transport agree with a change from ITG to TEM turbulence regimes, we do not observe a reduction in the core rotation at mid-radius, nor a rotation reversal.
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [3] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [6] ;  [7] ;  [7] ;  [8]
  1. College of William and Mary, Williamsburg, VA (United States)
  2. Univ. of California, Los Angeles, CA (United States)
  3. General Atomics, San Diego, CA (United States)
  4. National Fusion Research Institute, Daejeon (South Korea)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  6. VTT Technical Research Centre of Finland, Espoo (Finland)
  7. Univ. of California San Diego, La Jolla, CA (United States)
  8. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
OSTI Identifier:
1345359
Grant/Contract Number:
FC02-04ER54698; SC0007880; FG02-08ER54984; AC02-09CH11466; FG02-07ER54917; FG02-89ER53296; FG02-08ER54999; DAE-FG02-07ER54917; AC2-09CH11466; FG0-08ER54984; FSC0007880
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 55; Journal Issue: 11; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
College of William and Mary, Williamsburg, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; transport properties; particle flux; Tokamaks