title: Initial operation of a newly developed multichord motional Stark effect diagnostic in KSTAR.
abstract: A photo-elastic modulator based 25-chord motional Stark effect (MSE) diagnostic has been successfully developed and commissioned in Korea Superconducting Tokamak Advanced Research. The diagnostic measures the radial magnetic pitch angle profile of the Stark splitting of a D-alpha line at 656.1 nm by the electric field associated with the neutral deuterium heating beam. A tangential view of the neutral beam provides a good spatial resolution of 1-3 cm for covering the major radius from 1.74 m to 2.28 m, and the time resolution is achieved at 10 ms. An in-vessel calibration before the vacuum closing as well as an in situ calibration during the tokamak operation was performed by means of specially designed polarized lighting sources. In this work, we present the final design of the installed MSE diagnostic and the first results of the commissioning.
authors.affiliation: National Fusion Research Institute, Yuseong, Daejeon 305-333, South Korea.
authors.forename: J
authors.initials: J
authors.lastname: Chung
authors.affiliation: National Fusion Research Institute, Yuseong, Daejeon 305-333, South Korea.
authors.forename: J
authors.initials: J
authors.lastname: Ko
authors.affiliation: National Fusion Research Institute, Yuseong, Daejeon 305-333, South Korea.
authors.forename: H
authors.initials: H
authors.lastname: Wi
authors.affiliation: Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Messmer
authors.affiliation: Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Schenkelaars
authors.affiliation: Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Scheffer
authors.affiliation: Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
authors.forename: R J E
authors.initials: RJ
authors.lastname: Jaspers