2,068 research outputs found
A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade
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 field) and
σ
(perpendicular to the electric field) lines of
the Balmer line D
α
. The technical properties of the system are described. The calibration procedures
are discussed and first measurements are presentedEuropean Union (EUROfusion 633053)European Union (EUROfusion Grant WP14-FRF-IPP)Ministerio de Economía y Competitividad (Grant No. FJCI-201422139
Impurity and Trace Tritium Transport in Tokamak Edge Turbulence
The turbulent transport of impurity or minority species, as for example
Tritium, is investigated in drift-Alfv\'en edge turbulence. The full effects of
perpendicular and parallel convection are kept for the impurity species. The
impurity density develops a granular structure with steep gradients and locally
exceeds its initial values due to the compressibility of the flow. An
approximate decomposition of the impurity flux into a diffusive part and an
effective convective part (characterized by a pinch velocity) is performed and
a net inward pinch effect is recovered. The pinch velocity is explained in
terms of Turbulent Equipartition and is found to vary poloidally. The results
show that impurity transport modeling needs to be two-dimensional, considering
besides the radial direction also the strong poloidal variation in the
transport coefficients.Comment: 12 Pages, 5 Figure
A fast edge charge exchange recombination spectroscopy system at the ASDEX Upgrade tokamak
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 recently refurbished with new lines of sight.
Construction features, calibration methods, and initial measurements obtained with the new setup will
be presented.European Commission (EUROfusion 633053
On the mutual effect of ion temperature gradient instabilities and impurity peaking in the reversed field pinch
The presence of impurities is considered in gyrokinetic calculations of ion
temperature gradient (ITG) instabilities and turbulence in the reversed field
pinch device RFX-mod. This device usually exhibits hollow Carbon/Oxygen
profiles, peaked in the outer core region. We describe the role of the
impurities in ITG mode destabilization, and analyze whether ITG turbulence is
compatible with their experimental gradients.Comment: 19 pages, 9 figures, accepted for publication in Plasma Phys.
Control. Fusio
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