A self-calibrating Thomson scattering technique, based on using two lasers of different wavelength and never implemented before in a fusion experiment, is tested for the first time in RFX-mod. The method employs two laser systems, Nd:YAG (λ = 1064 nm) and Nd:YLF (λ = 1053 nm), fired in sync through the same plasma volume. The combination of the two scattered spectra, individually recorded, is used to simultaneously obtain the measurements of the electron temperature and the relative calibration coefficients of the polychromator spectral channels sensitivities This work is a continuation of the dual-angle technique, a similar alternative method. Due to the small difference in the wavelengths of the two lasers, the sensitivity of this method is low in RFX-mod and reliable measurements of the calibration coefficients could not be obtained on a shot-to-shot basis, but only with a statistical analysis of a reasonable number of pairs of laser shots with good signal-to-noise ratio. The dual-laser method can be applied to most fusion devices and could provide continuous online monitoring of the spectral transmission of the detection system. This may prove essential in larger devices (ITER), where access for traditional calibration is difficult.

MC CORMACK, O., Giudicotti, L., Fassina, A., Pasqualotto, R. (2017). Dual-laser, self-calibrating Thomson scattering measurements in RFX-mod. PLASMA PHYSICS AND CONTROLLED FUSION, 59(5) [10.1088/1361-6587/aa6692].

Dual-laser, self-calibrating Thomson scattering measurements in RFX-mod

MC CORMACK O. B.
Primo
;
2017

Abstract

A self-calibrating Thomson scattering technique, based on using two lasers of different wavelength and never implemented before in a fusion experiment, is tested for the first time in RFX-mod. The method employs two laser systems, Nd:YAG (λ = 1064 nm) and Nd:YLF (λ = 1053 nm), fired in sync through the same plasma volume. The combination of the two scattered spectra, individually recorded, is used to simultaneously obtain the measurements of the electron temperature and the relative calibration coefficients of the polychromator spectral channels sensitivities This work is a continuation of the dual-angle technique, a similar alternative method. Due to the small difference in the wavelengths of the two lasers, the sensitivity of this method is low in RFX-mod and reliable measurements of the calibration coefficients could not be obtained on a shot-to-shot basis, but only with a statistical analysis of a reasonable number of pairs of laser shots with good signal-to-noise ratio. The dual-laser method can be applied to most fusion devices and could provide continuous online monitoring of the spectral transmission of the detection system. This may prove essential in larger devices (ITER), where access for traditional calibration is difficult.
Articolo in rivista - Articolo scientifico
dual laser; ITER; plasma diagnostics; RFX-mod; self calibration; Thomson scattering
English
2017
59
5
055021
reserved
MC CORMACK, O., Giudicotti, L., Fassina, A., Pasqualotto, R. (2017). Dual-laser, self-calibrating Thomson scattering measurements in RFX-mod. PLASMA PHYSICS AND CONTROLLED FUSION, 59(5) [10.1088/1361-6587/aa6692].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/287938
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