TY - JOUR
T1 - Inference of α-particle density profiles from ITER collective Thomson scattering
AU - Rasmussen, J.
AU - Stejner, M.
AU - Jensen, T.
AU - Klinkby, Esben Bryndt
AU - Korsholm, Søren Bang
AU - Larsen, A.W.
AU - Leipold, Frank
AU - Nielsen, S.K.
AU - Salewski, Mirko
PY - 2019
Y1 - 2019
N2 -
The primary purpose of the collective Thomson scattering (CTS) diagnostic at ITER is to measure the properties of fast-ion populations, in particular those of fusion-born -particles. Based on the present design of the diagnostic, we compute and fit synthetic CTS spectra for the ITER baseline plasma scenario, including the effects of noise, refraction, multiple fast-ion populations, and uncertainties on nuisance parameters. As part of this, we developed a model for CTS that incorporates spatial effects of frequency-dependent refraction. While such effects will distort the measured ITER CTS spectra, we demonstrate that the true -particle densities can nevertheless be recovered to within ∼10% from noisy synthetic spectra, using existing fitting methods that do not take these spatial effects into account. Under realistic operating conditions, we thus find the predicted performance of the ITER CTS system to be consistent with the ITER measurement requirements of a 20% accuracy on inferred -particle density profiles at 100 ms time resolution.
AB -
The primary purpose of the collective Thomson scattering (CTS) diagnostic at ITER is to measure the properties of fast-ion populations, in particular those of fusion-born -particles. Based on the present design of the diagnostic, we compute and fit synthetic CTS spectra for the ITER baseline plasma scenario, including the effects of noise, refraction, multiple fast-ion populations, and uncertainties on nuisance parameters. As part of this, we developed a model for CTS that incorporates spatial effects of frequency-dependent refraction. While such effects will distort the measured ITER CTS spectra, we demonstrate that the true -particle densities can nevertheless be recovered to within ∼10% from noisy synthetic spectra, using existing fitting methods that do not take these spatial effects into account. Under realistic operating conditions, we thus find the predicted performance of the ITER CTS system to be consistent with the ITER measurement requirements of a 20% accuracy on inferred -particle density profiles at 100 ms time resolution.
KW - ITER
KW - α-particles
KW - Collective Thomson scattering
U2 - 10.1088/1741-4326/ab2f50
DO - 10.1088/1741-4326/ab2f50
M3 - Journal article
SN - 0029-5515
VL - 59
JO - Nuclear Fusion
JF - Nuclear Fusion
IS - 9
M1 - 096051
ER -