Charge exchange recombination spectroscopy on a diagnostic hydrogen beam—measuring impurity rotation and radial electric field at the tokamak TEXTOR

Abstract

To cite this version:J W Coenen, M Clever, U Samm, O Schmitz, B Schweer, et al.. Charge exchange recombination spectroscopy on a diagnostic hydrogen beammeasuring impurity rotation and radial electric field at the tokamak TEXTOR. Journal of Physics B: Atomic, Molecular and Optical Physics, IOP Publishing, 2010, 43 (14) Abstract. In this work we present an overview on the CXRS diagnostic operated with the modulated diagnostic hydrogen beam at the Tokamak TEXTOR. The diagnostic setup combines two observation systems used for the measurement of the poloidal (v pol ) and the toroidal (v tor ) ion velocity component.At TEXTOR a differential Doppler spectroscopy approach (accurate absolute rotation scale) is combined with the high intensity and spatial resolution of a direct imaging system necessary for accurate poloidal rotation measurements on a shot by shot basis. This setup allows the full utilization of the a 2D CCD detector in the spectral and radial direction. In case of the poloidal system this allows spatial resolution in the range of mm to cm depending on the intensity requirements for the velocity. The toroidal system is comprised of a fiber-optic array. The combination of the two measurements with a low power diagnostic beam can in principal be operated during any available heating scenario without interfering with the discharge. Time resolution is limited by the necessary averaging process, typically a stable plateau of 3 s during a TETXOR pulse is used. The TEXTOR tokamak has the ability to apply momentum input with two tangential neutral beam heating injectors, allowing for measurements under various heating and momentum input scenarios. With the presented diagnostic half the plasma minor radius at a spatial resolution of ∼ 1cm is covered. With the CVI line at 529.053 nm an accuracy of 0.7km/s for the poloidal and ∼ 5 km/s for the toroidal system is given. The temperature is measured with an accuracy of a few eV. The presented work illustrates the capability of the system during a toroidal momentum scan, showing the self-consistent determination of the radial electric field from experimental CXRS data based on the radial force balance.Confidential: not for distribution.

Toroidal mode number determination of ELM associated phenomena on ASDEX Upgrade

“…The phase velocity can now be calculated from the mode velocity, given by the measured f/n values and the poloidal part of the E × B velocity v p,E×B (r) = E(r)× Bt(r) Bt(r) 2 via Equation 4, where the radial electric field E is measured with the charge exchange recombination spectroscopy (CXRS) diagnostic [18,19]. Conversely, the mode can be localized with this equation if the phase velocity is known.…”

Emission of fast hydrogen atoms at a plasma–solid interface in a low density plasma containing noble gases

“…Furthermore, information on angular or energy distribution is conserved, as collisional quenching of excited levels by electrons or ions remains inefficient. Spectroscopic observations in the present experiments were obtained from two spectrometers previously installed at the tokamak TEXTOR [28]. The highresolution instrument utilises Echelle grating in a highorder (≈ 40) Littrow configuration with a dispersion of about 0.7-1.0Å/mm, a focal length of 1000 mm, groove density of 79 grooves/mm and a blaze angle of 76 • .…”

Capabilities of Spectroscopic Diagnostics CXRS in T-10 Tokamak

“…К числу наиболее важных параметров, требующих детального и надёжного измерения в условиях современных токамаков и будущего токамака-реактора, относятся такие параметры, как величина и профиль ионной температуры Ti(r), скорости вращения шнура, а также концентрации ядер примесей nZ(r) в плазме. Базовой диагностикой, позволяющей обеспечить локальные измерения этих параметров в условиях токамака, является CXRS-диагностика (Charge eXchange Recombination Spectroscopy), развитая на Т-10 [1], а также на многих других плазменных установках [2][3][4][5][6].…”