title: Multi-view fast-ion D-alpha spectroscopy diagnostic at ASDEX Upgrade.
abstract: A novel fast-ion D-alpha (FIDA) diagnostic that is based on charge exchange spectroscopy has been installed at ASDEX Upgrade. The diagnostic uses a newly developed high-photon-throughput spectrometer together with a low-noise EM-CCD camera that allow measurements with 2 ms exposure time. Absolute intensities are obtained by calibrating the system with an integrating sphere and the wavelength dependence is determined to high accuracy using a neon lamp. Additional perturbative contributions to the spectra, such as D2-molecular lines, the Stark broadened edge D-alpha emission, and passive FIDA radiation have been identified and can be subtracted or avoided experimentally. The FIDA radiation from fast deuterium ions after charge exchange reactions can therefore be analyzed continuously without superimposed line emissions at large Doppler shifts. Radial information on the fast ions is obtained from radially distributed lines of sight. The investigation of the fast-ion velocity distribution is possible due to three different viewing geometries. The independent viewing geometries access distinct parts of the fast-ion velocity space and make tomographic reconstructions possible.
authors.affiliation: Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Geiger
authors.forename: R
authors.initials: R
authors.lastname: Dux
authors.forename: R M
authors.initials: RM
authors.lastname: McDermott
authors.forename: S
authors.initials: S
authors.lastname: Potzel
authors.forename: M
authors.initials: M
authors.lastname: Reich
authors.forename: F
authors.initials: F
authors.lastname: Ryter
authors.forename: M
authors.initials: M
authors.lastname: Weiland
authors.forename: D
authors.initials: D
authors.lastname: Wünderlich
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Munoz