Correlation ECE diagnostic in Alcator C-Mod

Journal Article · Thu Mar 12 00:00:00 EDT 2015 · EPJ Web of Conferences

DOI:https://doi.org/10.1051/epjconf/20158703007· OSTI ID:1214643

Sung, C. ^[1]; White, A. E. ^[1]; Howard, N. T. ^[1]; Mikkelsen, D. ^[2]; Irby, J. ^[1]; Leccacorvi, R. ^[1]; Vieira, R. ^[1]; Oi, C. ^[1]; Rice, J. ^[1]; Reinke, M. ^[1]; Gao, C. ^[1]; Ennever, P. ^[1]; Porkolab, M. ^[1]; Churchill, R. ^[1]; Theiler, C. ^[1]; Walk, J. ^[1]; Hughes, J. ^[1]; Hubbard, A. ^[1]; Greenwald, M. ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Correlation ECE (CECE) is a diagnostic technique that allows measurement of small amplitude electron temperature, Te, fluctuations through standard cross-correlation analysis methods. In Alcator C-Mod, a new CECE diagnostic has been installed[Sung RSI 2012], and interesting phenomena have been observed in various plasma conditions. We find that local Te fluctuations near the edge (ρ ~ 0:8) decrease across the linearto- saturated ohmic confinement transition, with fluctuations decreasing with increasing plasma density[Sung NF 2013], which occurs simultaneously with rotation reversals[Rice NF 2011]. Te fluctuations are also reduced across core rotation reversals with an increase of plasma density in RF heated L-mode plasmas, which implies that the same physics related to the reduction of Te fluctuations may be applied to both ohmic and RF heated L-mode plasmas. In I-mode plasmas, we observe the reduction of core Te fluctuations, which indicates changes of turbulence occur not only in the pedestal region but also in the core across the L/I transition[White NF 2014]. The present CECE diagnostic system in C-Mod and these experimental results are described in this paper.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-09CH11466
• OSTI ID: 1214643
• Journal Information: EPJ Web of Conferences, Journal Name: EPJ Web of Conferences Vol. 87; ISSN 2100-014X
• Publisher: EDP Sciences
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY