A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark e ff ect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric...
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September 17, 2018 (v1)PublicationUploaded on: March 1, 2023
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April 28, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: December 5, 2022 -
May 9, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: December 4, 2022 -
April 11, 2022 (v1)Publication
The presence of helium is fundamentally connected to the performance of a fusion reactor, as fusion-produced helium is expected to heat the plasma bulk, while He 'ash' accumulation dilutes the fusion fuel. An understanding of helium transport via experimentally validated theoretical models of the low-Z impurity turbulent transport is...
Uploaded on: March 25, 2023 -
September 17, 2018 (v1)Publication
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...
Uploaded on: March 27, 2023 -
April 4, 2022 (v1)Publication
The access to fast measurements, i.e. Δt ≈ 100 µs, of the ions and the electrons during an entire edge localized cycle (ELM) reveals asymmetries in the recovery of the maximum edge gradients. Different magnetic fluctuations are found to correlate with the saturation of the edge ion temperature (Ti), electrons temperature (Te) and density (ne)...
Uploaded on: March 1, 2023 -
September 17, 2018 (v1)Publication
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...
Uploaded on: December 4, 2022 -
May 25, 2018 (v1)Publication
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...
Uploaded on: December 4, 2022 -
April 13, 2022 (v1)Publication
A new thermal helium beam diagnostic has been implemented as plasma edge diagnostic at the ASDEX Upgrade (AUG) tokamak. The helium beam is built to measure the electron density ne and temperature Te simultaneously with high spatial and temporal resolution in order to investigate steady-state as well as fast transport processes in the plasma...
Uploaded on: March 25, 2023 -
October 8, 2018 (v1)Publication
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...
Uploaded on: December 4, 2022 -
April 25, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: December 2, 2022 -
April 29, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: March 25, 2023 -
May 10, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: March 1, 2023 -
September 17, 2018 (v1)Publication
The ion heat transport in the pedestal of H-mode plasmas is investigated in various H-mode discharges with different pedestal ion collisionalities. Interpretive modelling suggests that in all analyzed discharges the ion heat diffusivity coefficient, χ i , in the pedestal is close to the neoclassical prediction within the experimental...
Uploaded on: March 1, 2023 -
September 23, 2024 (v1)Publication
Ion temperature, rotation, and density are key parameters to evaluate the performance of present and future fusion reactors. These parameters are critical for understanding ion heat, momentum, and particle transport, making it mandatory to properly diagnose them. A common technique to measure these properties is charge exchange recombination...
Uploaded on: September 24, 2024 -
April 29, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: December 4, 2022 -
April 6, 2022 (v1)Publication
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...
Uploaded on: March 25, 2023 -
April 26, 2022 (v1)Publication
EUROfusion Consortium 633053
Uploaded on: December 4, 2022 -
August 29, 2022 (v1)Publication
We present a non-parametric inference of impurity transport coefficients by using charge exchange recombination spectroscopy measurements of Ne X, Ne VIII, O VIII, and C VI lines. Due to their close atomic numbers, neon, oxygen and carbon impurity ions are assumed to have the same diffusion coefficient D and convection velocity v. Unlike...
Uploaded on: March 25, 2023