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

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3481166· OSTI ID:1025859

Shafer, M W ^[1]; Battaglia, D J ^[1]; Unterberg, Ezekial A ^[2]; Evans, T E ^[3]; Hillis, Donald Lee ^[2]; Maingi, R ^[1]

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1. Oak Ridge National Laboratory (ORNL)
2. ORNL
3. General Atomics, San Diego

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(e) similar to 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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1025859
• Journal Information: Review of Scientific Instruments, Vol. 81, Issue 10; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AMPLIFICATION
BERYLLIUM
DESIGN
DOUBLET-3 DEVICE
EMISSIVITY
ISLANDS
PLASMA
RADIATIONS
RESOLUTION
SHIELDING
SIGNAL-TO-NOISE RATIO
TOPOLOGY
CAMERA