ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
The soft x-ray and extreme ultraviolet (XUV) impurity emissions from tokamaks (10 Å〈λ〈304 Å) have been extensively studied with high-resolution grazing incidence spectrographs, and atomic physics models predicting spectral line brightnesses have been benchmarked against these experimental data. This, together with the ability to perform large amounts of accurate atomic physics computations, enables the relaxation on the requirement for high resolution spectra. The multilayer mirror (MLM) is a low resolving power (λ/δ λ〈100) XUV dispersive/reflective optical element that obeys the Bragg law of reflection. MLM based monitors are compact, high-photon-throughput diagnostics capable of extracting XUV emissions of impurities from the harsh environment of large fusion reactor-type devices. We will show how atomic physics modeling can be used to extract the XUV spectral line brightnesses measured with low-resolution, high-photon-throughput, MLM-based devices. The Plasma Spectroscopy Group at The Johns Hopkins University has investigated the application of MLM based diagnostics for magnetically confined fusion plasmas: MLM based monitors have been constructed for and extensively used on DIII–D, Alcator C-Mod, TEXT, Phaedrus-T, and CDX-U to study the impurity behavior of elements ranging from He to Mo. Experiments were also performed in which MLMs were irradiated to a fast neutron fluence of 1.1×1019 n cm−2 at 270–300 °C, and the preliminary results indicate that MLMs would be a good first wall reflector for fusion plasmas. Future applications of MLM based devices to study divertor coolants (Ne, Ar, and Kr emissions) and "killer pellet" (W emissions) experiments will also be discussed. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1147920
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