2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3481166· OSTI ID:22058742

Shafer, M W; Battaglia, D J; Unterberg, E A; Hillis, D L; Maingi, R ^[1]; Evans, T E ^[2]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

A new tangential two-dimensional soft x-ray imaging system (SXRIS) is being designed to examine the edge island structure in the lower X-point region of DIII-D. Plasma shielding and/or amplification of the calculated vacuum islands may play a role in the suppression of edge-localized modes via resonant magnetic perturbations (RMPs). The SXRIS is intended to improve the understanding of three-dimensional (3D) phenomena associated with RMPs. This system utilizes a tangential view with a pinhole imaging system and spectral filtering with beryllium foils. SXR emission is chosen to avoid line radiation and allows suitable signal at the top of a H-mode pedestal where T{sub e}{approx}1-2 keV. A synthetic diagnostic calculation based on 3D SXR emissivity estimates is used to help assess signal levels and resolution of the design. A signal-to-noise ratio of 10 at 1 cm resolution is expected for the perturbed signals, which are sufficient to resolve most of the predicted vacuum island sizes.

• OSTI ID: 22058742
• Journal Information: Review of Scientific Instruments, Vol. 81, Issue 10; Other Information: (c) 2010 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BERYLLIUM
DESIGN
DISTURBANCES
DOUBLET-3 DEVICE
EDGE LOCALIZED MODES
EMISSIVITY
H-MODE PLASMA CONFINEMENT
PLASMA
SHIELDING
SIGNAL-TO-NOISE RATIO
SOFT X RADIATION
THREE-DIMENSIONAL CALCULATIONS
TOPOLOGY
X-RAY EMISSION ANALYSIS