Implementation of high-resolution spectroscopy for ion (and electron) temperature measurements of the divertor plasma in the Tokamak à configuration variable

Martinelli, L.; Mikitchuck, D.; Duval, B. P.; Andrèbe, Y.; Blanchard, P.; Février, O.; Gorno, S.; Elaian, H.; Linehan, B.; Perek, A.; Stollberg, Christine; Vincent, Benjamin

doi:10.1063/5.0114538

Cited by 5 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The cameras operated at 200 Hz with exposure times dynamically adjusting between 0.2 ms to 5.0 ms to prevent saturation. Divertor spectrometers which viewed the divertor leg were utilized for the purpose of cross-checking the MANTIS measurements [74]. The emissivity profiles measured by MANTIS were found to accurately predict the brightness observations of the divertor spectrometers.…”

Section: Methodsmentioning

confidence: 99%

Validation of 2D Te and ne measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

et al. 2023

Self Cite

View full text Add to dashboard Cite

Multi-spectral imaging of helium atomic emission (HeMSI) has been used to create 2D poloidal maps of Te and ne in TCV’s divertor. To achieve these measurements, TCV’s MANTIS multispectral cameras simultaneously imaged four He I lines (2 singlet and 2 triplet) and a He II line (468nm) from passively present He and He+. The images, which were absolutely calibrated and covered the whole divertor region, were inverted through the assumption of toroidal symmetry to create emissivity profiles and, consequently, line-ratio profiles. A collisional-radiative model (CRM) was applied to the line-ratio profiles to produce 2D poloidal maps of Te and ne. The collisional-radiative modeling was accomplished with the Goto helium CRM code which accounts for electron-impact excitation and deexcitation (EIE), and electron-ion recombination (EIR) with He+. The HeMSI Te and ne measurements were compared with co-local Thomson scattering measurements. The two sets of measurements exhibited good agreement for ionizing plasmas: (5 eV ≤ Te ≤ 60 eV, and 2 × 1018 m-3 ≤ ne ≤ 3 × 1019 m-3) in the case of majority helium plasmas, and (10 eV ≤ Te ≤ 40 eV, 2 × 1018 m-3 ≤ ne ≤ 3 × 1019 m-3) in the case of majority deuterium plasmas. However, there were instances where HeMSI measurements diverged from Thomson scattering. When Te ≤ 10 eV in majority deuterium plasmas, HeMSI deduced inaccurately high values of Te. This disagreement cannot be rectified within the CRM’s EIE and EIR framework. Second, on sporadic occasions within the private flux region, HeMSI produced erroneously high measurements of ne. Multi-spectral imaging of Helium emission has been demonstrated to produce accurate 2D poloidal maps of Te and ne within the divertor of a tokamak for plasma conditions relevant to contemporary divertor studies.

show abstract

Section: Methodsmentioning

confidence: 99%

Validation of 2D Te and ne measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…The DSS installed in TCV (figure 1(a)) provides measurements of the line-integrated visible radiation at different wavelengths, corresponding to different atomic processes [24]. The DSS system has 30 chords along which it is possible to measure the wavelength spectra with a spectral resolution of up to 0.02 nm [16]. The measurement is a line integral of the emission along a given chord.…”

Section: Divertor Spectroscopy Systemmentioning

confidence: 99%

Validation of SOLPS-ITER simulations against the TCV-X21 reference case

Wang,

Colandrea,

Oliveira

et al. 2024

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

This paper presents a quantitative validation of SOLPS-ITER simulations against the TCV-X21 reference case and provides insights into the neutral dynamics and ionization source distribution in this scenario. TCV-X21 is a well-diagnosed diverted L-mode sheath-limited plasma scenario in both toroidal field directions, designed specifically for the validation of turbulence codes [D.S. Oliveira, T. Body, et al 2022 Nucl. Fusion 62 096001]. Five new, neutrals-related observables are added here to the extensive, publicly available TCV-X21 dataset. These are three deuterium Balmer lines in the divertor and neutral pressure measurements in the common and private flux regions. The quantitative agreement metric used in the validation is combined with the conjugate gradient method to approach the SOLPS-ITER input parameters that return the best overall agreement with the experiment. A proof-of-principle test of this method results in a modest improvement in the level-of-agreement; the shortcomings impacting the result and how to improve the methodology are discussed. Alternatively, a scan of the particle and heat diffusion coefficients shows an improvement of 10.4% in the level-of-agreement, approximately twice as high as that achieved by the gradient method. This result is found for an increased transport coefficient compared to what is usually used for TCV L-mode plasmas. The simulations further indicate that 65% of the total ionization occurs in the SOL, from which 70% in the divertor regions, despite being a sheath-limited regime, motivating the inclusion of self-consistent neutral models in future turbulence simulations on the path towards improved agreement with the experiment.

show abstract

“…On current tokamaks, spectroscopic systems are installed to investigate the light emitted by the plasma, especially from the plasma in the divertor region. The divertor spectroscopic system (DSS) [14] of TCV is shown in Figure 1.2a. With all these line-of-sight, the light emitted from different parts of the plasma is measured.…”

Section: Spectroscopymentioning

confidence: 99%

“…To validate the synthetic diagnostic, the synthetic measurements are compared with the real measurements from the divertor spectroscopic system (DSS) [14], with lines-of-sight shown in Figure 2.1, for discharge #69144 [18]. During this experiment, the NII impurity emission front position was controlled to three increasingly higher points, progressively increasing the impurity concentration in the divertor and reducing target ion flux.…”

Section: Synthetic Spectroscopymentioning

confidence: 99%

Demonstration of a Sparse Sensor Placement Technique to the Limited Diagnostic Set in a Fusion Power Plant

Raukema,

Bosman,

Classen

et al. 2023

Preprint

View full text Add to dashboard Cite

Implementation of high-resolution spectroscopy for ion (and electron) temperature measurements of the divertor plasma in the Tokamak à configuration variable

Cited by 5 publications

References 25 publications

Validation of 2D Te and ne measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

Validation of 2D Te and ne measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

Validation of SOLPS-ITER simulations against the TCV-X21 reference case

Demonstration of a Sparse Sensor Placement Technique to the Limited Diagnostic Set in a Fusion Power Plant

Contact Info

Product

Resources

About