Conceptual design of Thomson scattering system with high wavelength resolution in magnetically confined plasmas for electron phase-space measurements

Fuente: arXiv
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Autores principales: Sakai, Kentaro, Tomita, Kentaro, Hoshi, Takeo, Nakano, Akito, Goto, Motoshi, Nagaoka, Kenichi, Yasuhara, Ryo
Formato: Preprint
Publicado: 2025
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author Sakai, Kentaro
Tomita, Kentaro
Hoshi, Takeo
Nakano, Akito
Goto, Motoshi
Nagaoka, Kenichi
Yasuhara, Ryo
author_facet Sakai, Kentaro
Tomita, Kentaro
Hoshi, Takeo
Nakano, Akito
Goto, Motoshi
Nagaoka, Kenichi
Yasuhara, Ryo
contents We discuss the conceptual design of a spatially-resolved spectroscopy system of Thomson scattering with high wavelength resolution capable of measuring the shape of electron velocity distribution functions in magnetically confined plasmas. We design a spatially-resolved spectrometer with 2560 wavelength channels. The estimated number of scattered photons in a single spectrometer channel is much larger than unity under the experimental setup and plasma parameters of the Compact Helical Device (CHD), indicating sufficient photon statistics for single-shot measurements. Simulations of the scattered spectra show that the signal-to-noise ratio exceeds 5 even under the most unfavorable conditions expected in CHD at full spectral resolution, and further improves with post-processing pixel binning. Bayesian inference applied to the simulated spectra demonstrates that the inferred plasma parameters agree with the input values within the estimated uncertainties. Comparisons between spectra generated from non-Maxwellian electron velocity distribution functions and their Maxwellian fits indicate that deviations from Maxwellian distributions can be identified using the proposed system.
format Preprint
id arxiv_https___arxiv_org_abs_2511_06330
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Conceptual design of Thomson scattering system with high wavelength resolution in magnetically confined plasmas for electron phase-space measurements
Sakai, Kentaro
Tomita, Kentaro
Hoshi, Takeo
Nakano, Akito
Goto, Motoshi
Nagaoka, Kenichi
Yasuhara, Ryo
Plasma Physics
We discuss the conceptual design of a spatially-resolved spectroscopy system of Thomson scattering with high wavelength resolution capable of measuring the shape of electron velocity distribution functions in magnetically confined plasmas. We design a spatially-resolved spectrometer with 2560 wavelength channels. The estimated number of scattered photons in a single spectrometer channel is much larger than unity under the experimental setup and plasma parameters of the Compact Helical Device (CHD), indicating sufficient photon statistics for single-shot measurements. Simulations of the scattered spectra show that the signal-to-noise ratio exceeds 5 even under the most unfavorable conditions expected in CHD at full spectral resolution, and further improves with post-processing pixel binning. Bayesian inference applied to the simulated spectra demonstrates that the inferred plasma parameters agree with the input values within the estimated uncertainties. Comparisons between spectra generated from non-Maxwellian electron velocity distribution functions and their Maxwellian fits indicate that deviations from Maxwellian distributions can be identified using the proposed system.
title Conceptual design of Thomson scattering system with high wavelength resolution in magnetically confined plasmas for electron phase-space measurements
topic Plasma Physics
url https://arxiv.org/abs/2511.06330