Core density turbulence in the HSX Stellarator

Journal Article · Fri Oct 23 00:00:00 EDT 2015 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/55/12/123003· OSTI ID:1266859

Deng, C. B. ^[1]; Brower, D. L. ^[1]; Anderson, D. T. ^[2]; Anderson, F. S. B. ^[2]; Briesemeister, Alexis R. ^[3]; Likin, K. M. ^[2]

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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)

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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1266859
• Journal Information: Nuclear Fusion, Vol. 55, Issue 12; ISSN 0029-5515
• Publisher: IOP Science
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
stellarator
turbulence
transport
TEMPERATURE-GRADIENT TURBULENCE
SIMULATION