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This content will become publicly available on October 23, 2016

Title: Core density turbulence in the HSX Stellarator

Broadband turbulent density fluctuations are explored in the helically symmetric stellarator experiment (HSX) by investigating changes related to plasma heating power and location. No fluctuation response is observed to occur with large changes in electron temperature and its gradient, thereby eliminating temperature gradient as a driving mechanism. Instead, measurements reveal that density turbulence varies inversely with electron density scale length. This response is consistent with density gradient drive as one might expect for trapped electron mode (TEM) turbulence. In general, the plasma stored energy and particle confinement are higher for discharges with reduced fluctuations in the plasma core. When the density fluctuation amplitude is reduced, increased plasma rotation is also evident suggesting a role is being played by intrinsic plasma flow.
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [2]
  1. Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy
  2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Electrical and Computer Engineering
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1266859
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 55; Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY stellarator; turbulence; transport; TEMPERATURE-GRADIENT TURBULENCE; SIMULATION