- By:
- Shafer, Morgan W; Battaglia, Devon J; Unterberg, Ezekial A; Evans, T.E.; Hillis, Donald L; Maingi, Rajesh
- Journal Name:
- Review of Scientific Instruments
- Volume:
- 81
- Issue Number:
- 10
- Publication Date:
- September 27, 2011
- View DOI Listing:
- https://doi.org/10.1063/1.3481166
Abstract
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.
