title: Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D.
abstract: An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in diverted and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. Demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Lasnier
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Allen
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Ellis
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Fenstermacher
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: McLean
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Meyer
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: K
authors.initials: K
authors.lastname: Morris
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
authors.forename: L G
authors.initials: LG
authors.lastname: Seppala
authors.affiliation: College of Optics, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: K
authors.initials: K
authors.lastname: Crabtree
authors.affiliation: General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Van Zeeland