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First 2D electron density measurements using Coherence Imaging Spectroscopy in the MAST-U Super-X divertor

Fuente: arXiv

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Bibliographic Details
Main Authors:	Lonigro, N., Doyle, R., Allcock, J. S., Lipschultz, B., Verhaegh, K., Bowman, C., Brida, D., Harrison, J., Myatra, O., Silburn, S., Theiler, C., Wijkamp, T. A., Team, MAST-U, Team, the EUROfusion Tokamak Exploitation
Format:	Preprint
Published:	2024
Subjects:	Plasma Physics
Online Access:	Acceder al recurso
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_version_	1866909174022012928
author	Lonigro, N. Doyle, R. Allcock, J. S. Lipschultz, B. Verhaegh, K. Bowman, C. Brida, D. Harrison, J. Myatra, O. Silburn, S. Theiler, C. Wijkamp, T. A. Team, MAST-U Team, the EUROfusion Tokamak Exploitation
author_facet	Lonigro, N. Doyle, R. Allcock, J. S. Lipschultz, B. Verhaegh, K. Bowman, C. Brida, D. Harrison, J. Myatra, O. Silburn, S. Theiler, C. Wijkamp, T. A. Team, MAST-U Team, the EUROfusion Tokamak Exploitation
contents	2D profiles of electron density and neutral temperature are inferred from multi-delay Coherence Imaging Spectroscopy data of divertor plasmas using a non-linear inversion technique. The inference is based on imaging the spectral line-broadening of Balmer lines and can differentiate between the Doppler and Stark broadening components by measuring the fringe contrast at multiple interferometric delays simultaneously. The model has been applied to images generated from simulated density profiles to evaluate its performance. Typical mean absolute errors of 30 percent are achieved, which are consistent with Monte Carlo uncertainty propagation accounting for noise, uncertainties in the calibrations, and in the model inputs. The analysis has been tested on experimental data from the MAST-U Super-X divertor, where it infers typical electron densities of 2-3 $10^{19}$ m$^{-3}$ and neutral temperatures of 0-2 eV during beam-heated L-mode discharges. The results are shown to be in reasonable agreement with the other available diagnostics.
format	Preprint
id	arxiv_https___arxiv_org_abs_2404_12021
institution	arXiv
publishDate	2024
record_format	arxiv
spellingShingle	First 2D electron density measurements using Coherence Imaging Spectroscopy in the MAST-U Super-X divertor Lonigro, N. Doyle, R. Allcock, J. S. Lipschultz, B. Verhaegh, K. Bowman, C. Brida, D. Harrison, J. Myatra, O. Silburn, S. Theiler, C. Wijkamp, T. A. Team, MAST-U Team, the EUROfusion Tokamak Exploitation Plasma Physics 2D profiles of electron density and neutral temperature are inferred from multi-delay Coherence Imaging Spectroscopy data of divertor plasmas using a non-linear inversion technique. The inference is based on imaging the spectral line-broadening of Balmer lines and can differentiate between the Doppler and Stark broadening components by measuring the fringe contrast at multiple interferometric delays simultaneously. The model has been applied to images generated from simulated density profiles to evaluate its performance. Typical mean absolute errors of 30 percent are achieved, which are consistent with Monte Carlo uncertainty propagation accounting for noise, uncertainties in the calibrations, and in the model inputs. The analysis has been tested on experimental data from the MAST-U Super-X divertor, where it infers typical electron densities of 2-3 $10^{19}$ m$^{-3}$ and neutral temperatures of 0-2 eV during beam-heated L-mode discharges. The results are shown to be in reasonable agreement with the other available diagnostics.
title	First 2D electron density measurements using Coherence Imaging Spectroscopy in the MAST-U Super-X divertor
topic	Plasma Physics
url	https://arxiv.org/abs/2404.12021