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Correlation ECE diagnostic in Alcator C-Mod

Authors :
Sung C.
White A. E.
Howard N. T.
Mikkelsen D.
Irby J.
Leccacorvi R.
Vieira R.
Oi C.
Rice J.
Reinke M.
Gao C.
Ennever P.
Porkolab M.
Churchill R.
Theiler C.
Walk J.
Hughes J.
Hubbard A.
Greenwald M.
Source :
EPJ Web of Conferences, Vol 87, p 03007 (2015)
Publication Year :
2015
Publisher :
EDP Sciences, 2015.

Abstract

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.

Subjects

Subjects :
Physics
QC1-999

Details

Language :
English
ISSN :
2100014X
Volume :
87
Database :
Directory of Open Access Journals
Journal :
EPJ Web of Conferences
Publication Type :
Academic Journal
Accession number :
edsdoj.6f806c3c74f3464cabcecbf717cd50bc
Document Type :
article
Full Text :
https://doi.org/10.1051/epjconf/20158703007