Core reflectometer density profile measurements on DIII-D

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1149481· OSTI ID:328548

Doyle, E J; Rhodes, T L; Peebles, W A; Zeng, L ^[1]

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1. Department of Electrical Engineering and Institute of Plasma and Fusion Research, University of California, Los Angeles, San Diego, California, 90095 (United States)

Measurements of core (normalized flux coordinate {rho}{le}0.3{endash}0.4) electron density profiles have been obtained on the DIII-D tokamak via a reflectometer system operating in the ordinary polarization (O mode). This system was developed and implemented for two primary reasons: first, there is a pressing need for core density profile measurements on DIII-D in plasmas with core transport barriers and centrally peaked profiles, and second, the measurements reported here further extend the demonstrated range of conditions in which reflectometry can provide reliable density profile measurements. As a test of the ability of reflectometry to measure such core profiles an existing DIII-D broadband frequency swept (FMCW) reflectometer system was converted to use O-mode propagation. This test system covers 50{endash}75 GHz, corresponding to densities of 3.1{endash}7.0{times}10{sup 19} m{sup {minus}3}. Using this system, core access has been investigated in medium density discharges. Results demonstrate that adequate signals, and hence, accurate profiles, can in fact be obtained to the plasma center in discharges with centrally peaked profiles. {copyright} {ital 1999 American Institute of Physics.}

• OSTI ID: 328548
• Report Number(s): CONF-980605--
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 1 Vol. 70; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA DENSITY
PLASMA DIAGNOSTICS
POLARIZATION
REFLECTION
TOKAMAK DEVICES