GEIGER , B.

Fast-ion Dα (FIDA) and collective Thomson scattering (CTS) diagnostics provide indirect measurements of fastion velocity distribution functions in magnetically confined plasmas. Here we present the first prescription for velocity-space tomographic inversion of CTS and FIDA measurements that can use CTS and FIDA measurements together and that...

We present the first measurement of a local fast-ion 2D velocity distribution function f (v , v⊥). To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion Dα (FIDA) light from the plasma centre in three views simultaneously. The measured spectra agree very well with synthetic spectra...

We compute tomographies of 2D fast-ion velocity distribution functions from synthetic collective Thomson scattering (CTS) and fast-ion Dα (FIDA) 1D measurements using a new reconstruction prescription. Contradicting conventional wisdom we demonstrate that one single 1D CTS or FIDA view suffices to compute accurate tomographies of arbitrary 2D...

A fast-ion D-alpha (FIDA) diagnostic has been developed for the fully tungsten coated ASDEX Upgrade (AUG) tokamak using 25 toroidally viewing lines of sight and featuring a temporal resolution of 10 ms. The diagnostic's toroidal geometry determines a well-defined region in velocity space which significantly overlaps with the typical fast-ion...

A comprehensive suite of diagnostics has allowed detailed measurements of the Alfven eigenmode (AE) spatial ´ structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1]. Reversed shear Alfven´ eigenmodes (RSAEs) and toroidal induced Alfven eigenmodes (TAEs) have been driven unstable by fast ions from ´ ICRH as well as...

In this work, a new type of high through-put Czerny-Turner spectrometer has been developed which allows us to acquire multiple channels simultaneously with a repetition time on the order of 10 μ s at different wavelengths. The spectrometer has been coupled to the edge charge exchange recom- bination system at ASDEX Upgrade which has been...

Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade allow to reconstruct the fast-ion phase space at several radial positions with decent energy and pitch resolution. These new diagnostic capabilities are applied to study the physics of 2nd harmonic ion cyclotron heating, which is a foreseen heating scenario for ITER. In...

A new core charge exchange recombination spectroscopy diagnostic has been installed in the ASDEX Upgrade tokamak that is capable of measuring the impurity ion temperature, toroidal rotation, and density on both the low field side (LFS) and high field side (HFS) of the plasma. The new system features 48 lines-of-sight (LOS) with a radial...

We present the first measurement of a local fast-ion 2D velocity distribution function f(v||, v⊥). To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion Dα (FIDA) light from the plasma centre in three views simultaneously. The measured spectra agree very well with synthetic spectra...

The analysis of the charge exchange measurements of helium is hindered by an additional emission contributing to the spectra, the helium 'plume' emission (Fonck et al 1984 Phys. Rev. A 29 3288), which complicates the interpretation of the measurements. The plume emission is indistinguishable from the active charge exchange signal when standard...

At ASDEX upgrade (AUG) a new framework for the evaluation of impurity densities based on measurements from charge exchange recombination spectroscopy (CXRS) diagnostics has been developed. The charge exchange impurity concentration analysis code, or CHICA, can perform these calculations for all of the beam-based CXRS diagnostics at AUG and is...

A feasibility study for a new edge main ion charge exchange recombination spectroscopy (CXRS) system at the ASDEX Upgrade tokamak has been carried out. This diagnostic uses the new edge fast-ion Dα (FIDA) spectrometers and the optical heads of the existing edge CXRS systems. Standard CXRS resolved temperature and rotation profiles rely on the...