Operation of two grating polychromators on TFTR and new observations of magnetohydrodynamic phenomena

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1146255· OSTI ID:7060121

Janos, A; McCarthy, M; Fredrickson, E; McGuire, K; Taylor, G ^[1]

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

A second grating polychromator instrument has been installed recently on the Tokamak Fusion Test Reactor device. Both this new instrument and the original one, at a different toroidal location, measure electron cyclotron emission from which electron temperature fluctuations and profiles can be obtained. This combination of instruments is designed to provide crucial information on both the poloidal and toroidal structure of magnetohydrodynamic phenomena internal to the TFTR plasma. These instruments are designed to operate within the high neutron flux environment of deuterium-tritium operation in TFTR. Already, this combination of instruments has proven extremely valuable in identifying toroidally nonaxisymmetric phenomena. In addition to toroidal mode numbers, these instruments have yielded valuable new information on the evolution of the structure of the temperature profile during both high-density and high-beta disruptions, and the precursors to these disruptions. In the high-density case, the fast growing (m,n)=(1,1) structure of a cold bubble is verified conclusively. In the high-beta case, a ballooning type of precursor, toroidally and poloidally localized, appears to play an important role in the disruption. Also, this combination of instruments has provided positive verification of the existence of locked and stationary modes, and the temporal evolution of these modes.

• DOE Contract Number: AC02-76CH03073
• OSTI ID: 7060121
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 66:1; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
700340 -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700370 -- Plasma Fluid & MHD Properties-- (1992-)
700410 -- Specific Fusion Devices & Experiments-- (1992-)
BALLOONING INSTABILITY
BREMSSTRAHLUNG
CLOSED PLASMA DEVICES
CYCLOTRON RADIATION
ELECTROMAGNETIC RADIATION
ELECTRON TEMPERATURE
FLUCTUATIONS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETOHYDRODYNAMICS
MEASURING INSTRUMENTS
MECHANICS
NEUTRON FLUX
PLASMA DIAGNOSTICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RADIATION FLUX
RADIATIONS
SPECTROMETERS
TFTR TOKAMAK
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VARIATIONS
X-RAY SPECTROMETERS