Calibration and test of the tangential phase contrast imaging diagnostic on CDX-U

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1147883· OSTI ID:452847

Lo, E; Nazikian, R; Stutman, D; Choe, W; Kaita, R ^[1]

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1. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States)

A novel CO{sub 2} laser-based tangential imaging diagnostic was completely calibrated and the system was tested on CDX-U plasmas. It was shown that localized, two-dimensional images of the plasma electron density fluctuations in the tokamak core can be obtained from a tangential imaging beam [E. Lo, J. Wright, and R. Nazikian, Rev. Sci. Instrum. {bold 66}, 1180 (1995)]. A variation of the Zernike phase mirror is used. Test measurements made on sound waves verify that the system will image phase variations placed at the object plane. An absolute sensitivity of {approx}1{times}10{sup 7} cm{sup {minus}3}/{radical}(Hz) was determined. A series of plasma measurements made on CDX-U is described. Results show that the plasma fluctuations are two to three orders of magnitude above the noise floor of the diagnostic. It is also verified that a high-pass cut-off wave number (from {approx}1 to 8 cm{sup {minus}1}) for the fluctuations can be selected by translating the phase mirror. The density fluctuation {ital k} spectrum is measured and found to peak at {approx}1{endash}3 cm{sup {minus}1}. {copyright} {ital 1997 American Institute of Physics.}

• Research Organization: Princeton Plasma Physics Laboratory
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 452847
• Report Number(s): CONF-960543--
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 2 Vol. 68; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CALIBRATION
CARBON DIOXIDE LASERS
DENSITY
ELECTRON DENSITY
FLUCTUATIONS
IMAGES
MIRRORS
OPTICAL SYSTEMS
PLASMA DENSITY
PLASMA DIAGNOSTICS
SENSITIVITY
TESTING
TOKAMAK DEVICES
plasma fluctuations
plasma toroidal confinement