Numerical simulation of a system for ion temperature measurement by Thomson scattering in a tokamak

Journal Article · Fri May 01 04:00:00 EDT 1981 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.329195· OSTI ID:6377819

Watterson, R L; Siegrist, M R; Dupertuis, M A; Morgan, P D; Green, M R

A numerical simulation of tokamak ion temperature measurement by collective laser Thomson scattering was performed including a Monte-Carlo technique to model the statistical properties of power spectrum estimation. The accuracy to which the ion temperature T/sub i/, may be determined under the influence of a finite laser pulse length, a limited signal-to-noise ratio, unequal electron and ion temperatures, and the presence of heavy impurities was investigated. It is found that the effects of low-frequency plasma turbulence and heavy impurities on the scattered spectrum may be mitigated (and the required heterodyne receiver intermediate frequency bandwidth reduced) by considering only the high-frequency portion of the scattered spectrum. A ratio of total scattered power to total noise power of 1 to 2 is shown to be sufficient to determine T/sub i/. A higher signal-to-noise ratio provides little enhancement in the accuracy of T/sub i/ determination. Improved values of T/sub i/ may be achieved by a longer laser pulse. A laser pulse at least 1 ..mu..sec long is required to measure T/sub i/ to within 10% with a signal-to-noise ratio of 2- and 2-GHz heterodyne receiver intermediate frequency bandwidth.

• Research Organization: Centre de Recherches en Physique des Plasmas, Association Euratom: Confederation Suisse, Ecole Polytechnique Federale de Lausanne, 21, Avenue des Bains, CH-1007, Lausanne, Switzerland.
• OSTI ID: 6377819
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 52:5; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700201* -- Fusion Power Plant Technology-- Blanket Engineering
ACCURACY
CLOSED PLASMA DEVICES
COMPUTERIZED SIMULATION
DATA
ELECTROMAGNETIC RADIATION
ELECTRON TEMPERATURE
ELECTRONIC EQUIPMENT
EQUIPMENT
HETERODYNE RECEIVERS
INELASTIC SCATTERING
INFORMATION
ION TEMPERATURE
LASER RADIATION
MATHEMATICAL MODELS
MICROWAVE EQUIPMENT
MONTE CARLO METHOD
NUMERICAL DATA
RADIATION EFFECTS
RADIATIONS
RADIO EQUIPMENT
SCATTERING
SIGNAL-TO-NOISE RATIO
SIMULATION
SPECTRA
TEMPERATURE MEASUREMENT
THEORETICAL DATA
THERMONUCLEAR DEVICES
THOMSON SCATTERING
TOKAMAK DEVICES
TURBULENCE