Enhancement of the FIDA diagnostic at ASDEX Upgrade for velocity space tomography. (11th January 2016)

• Record Type: Journal Article
• Authors: Weiland, M; Geiger, B; Jacobsen, A S; Reich, M; Salewski, M; Odstrčil, T
• Other Names: collab.
• Is Part Of: Plasma physics and controlled fusion. Volume 58:Number 2(2016:Feb.)
• Publication Date: 2016-01-11
• Subjects: tomography -- sawtooth -- crash -- transport -- Doppler -- spectroscopy; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/0741-3335/58/2/025012
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade are discussed. The diagnostic has been extended from three to five line of sight arrays with different angles to the magnetic field, and a spectrometer redesign allows the simultaneous measurement of red- and blue-shifted parts of the Doppler spectrum. These improvements make it possible to reconstruct the 2D fast-ion velocity distribution from the FIDA measurements by tomographic inversion under a wide range of plasma parameters. Two applications of the tomography are presented: a comparison between the distributions resulting from 60 keV and 93 keV neutral beam injection and a velocity-space resolved study of fast-ion redistribution induced by a sawtooth crash inside and outside the sawtooth inversion radius.