TY - JOUR
T1 - Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade
AU - Stejner Pedersen, Morten
AU - Nielsen, Stefan Kragh
AU - Jacobsen, Asger Schou
AU - Korsholm, Søren Bang
AU - Leipold, Frank
AU - Meo, Fernando
AU - Michelsen, Poul
AU - Moseev, Dmitry
AU - Rasmussen, Jesper
AU - Salewski, Mirko
AU - Schubert, M.
AU - Stober, J.
AU - Wagner, D. H.
PY - 2014
Y1 - 2014
N2 - Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.
AB - Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.
U2 - 10.1063/1.4894199
DO - 10.1063/1.4894199
M3 - Journal article
C2 - 25273723
SN - 0034-6748
VL - 85
SP - 093504
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 9
ER -