Design and operation of the multipulse Thomson scattering diagnostic on DIII-D

Conference · Sun Mar 01 00:00:00 EST 1992

OSTI ID:10136926

Carlstrom, T N; Campbell, G L; DeBoo, J C; Evanko, R; Greenfield, C M; Haskovec, J; Hsieh, C L; McKee, E; Snider, R T; Stockdale, R; Trost, P K; Thomas, M P ^[1]; Evans, J ^[2]

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1. General Atomics, San Diego, CA (United States)
2. Lawrence Livermore National Lab., CA (United States)

This paper describes the design and operation of a 40 spatial channel Thomson scattering system that uses multiple 20 Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. As many as eight lasers may be fired alternately for an average measurement frequency of 160 Hz, or they may be fired in rapid succession (< 10 kHz), producing a burst of pulses for measuring transient events. The high spatial resolution (1.3 cm) and wide dynamic range (10 eV to 20 keV) enable this system to resolve large electron density and temperature gradients formed at the plasma edge and in the scrape-off-layer during H-mode operation. These features provide a formidable tool for studying L-H transitions, edge localized modes (ELMs), beta limits, transport, and disruptions in an efficient manner suitable for large tokamak operation where shot-to-shot scans are impractical. The scattered light is dispersed by interference filter polychromators and detected by silicon avalanche photodiodes. Laser control and data acquisition are performed in real-time by a VME based microcomputer. Data analysis is performed by a MicroVAX 3400. Additional features of this system include real-time analysis capability, full statistical treatment of error bars based on the measured background light, and laser beam quality and alignment monitoring during plasma operation. Results of component testing, calibration, plasma operation, and error analysis are presented.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 10136926
• Report Number(s): GA-A-20849; CONF-920362-21; ON: DE92011393
• Resource Relation: Conference: 9. topical conference on high-temperature plasma diagnostics,Santa Fe, NM (United States),15-19 Mar 1992; Other Information: PBD: Mar 1992
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOUBLET-3 DEVICE
PLASMA DIAGNOSTICS
DESIGN
THOMSON SCATTERING
ELECTRON TEMPERATURE
TEMPERATURE GRADIENTS
ELECTRON DENSITY
PLASMA SCRAPE-OFF LAYER
EDGE LOCALIZED MODES
CALIBRATION
DATA ACQUISITION SYSTEMS
H-MODE PLASMA CONFINEMENT
NEODYMIUM LASERS
700320
PLASMA DIAGNOSTIC TECHNIQUES AND INSTRUMENTATION