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

J W Coenen (1) , M Clever (1) , U Samm (1) , O Schmitz , B Schweer (1) , S Freutel (1) , H Stoschus (1) , B Unterberg (1)

1 Institut. für Energieforschung

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.

Mots clés: Physical Sciences

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, 2010, 43 (14), pp.144015. ⟨10.1088/0953-4075/43/14/144015⟩. ⟨hal-00597861⟩