First results from the Thomson scattering diagnostic on proto-MPEX

Journal Article · Tue Nov 15 04:00:00 EST 2016 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4959163· OSTI ID:22596551

Meitner, S.; Rapp, J. ^[1]; Ray, H.; Shaw, G. ^[2]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996 (United States)

A Thomson scattering (TS) diagnostic has been successfully implemented on the prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory. The diagnostic collects the light scattered by plasma electrons and spectroscopically resolves the Doppler shift imparted to the light by the velocity of the electrons. The spread in velocities is proportional to the electron temperature, while the total number of photons is proportional to the electron density. TS is a technique used on many devices to measure the electron temperature (T{sub e}) and electron density (n{sub e}) of the plasma. A challenging aspect of the technique is to discriminate the small number of Thomson scattered photons against the large peak of background photons from the high-power laser used to probe the plasma. A variety of methods are used to mitigate the background photons in Proto-MPEX, including Brewster angled windows, viewing dumps, and light baffles. With these methods, first results were measured from argon plasmas in Proto-MPEX, indicating T{sub e} ∼ 2 eV and n{sub e} ∼ 1 × 10{sup 19} m{sup −3}. The configuration of the Proto-MPEX TS diagnostic will be described and plans for improvement will be given.

• OSTI ID: 22596551
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 11 Vol. 87; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
BAFFLES
CONFIGURATION
DOPPLER EFFECT
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRONS
LASERS
ORNL
PHOTONS
PLASMA
THOMSON SCATTERING
VELOCITY
WINDOWS