title: Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements.
abstract: Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic on TEXTOR without a source of probing radiation in discharges with sawtooth oscillations, an elevation angle misalignment of 0.9° was found with an accuracy of 0.25°.
authors.affiliation: FOM DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein, The Netherlands. d.moseev@differ.nl
authors.forename: D
authors.initials: D
authors.lastname: Moseev
authors.forename: F
authors.initials: F
authors.lastname: Meo
authors.forename: S B
authors.initials: SB
authors.lastname: Korsholm
authors.forename: H
authors.initials: H
authors.lastname: Bindslev
authors.forename: V
authors.initials: V
authors.lastname: Furtula
authors.forename: M
authors.initials: M
authors.lastname: Kantor
authors.forename: F
authors.initials: F
authors.lastname: Leipold
authors.forename: P K
authors.initials: PK
authors.lastname: Michelsen
authors.forename: S K
authors.initials: SK
authors.lastname: Nielsen
authors.forename: M
authors.initials: M
authors.lastname: Salewski
authors.forename: M
authors.initials: M
authors.lastname: Stejner