A new thermal helium beam diagnostic has been implemented in the outer lower divertor of the ASDEX Upgrade tokamak. The purpose of this diagnostic is to measure two-dimensional profiles of electron density (ne) and temperature (Te) with high temporal and spatial resolution. The geometry of the lines of sight is chosen to avoid the influence of prompt recycling and to optimize the resolution without significantly impacting the divertor structure. Moreover, the effect of long-term helium recycling has been analyzed, and its amplitude compared to the active signal is negligible. Finally, the reconstruction of ne and Te is done via a collisional radiative model, while a static and a dynamic model were implemented and compared with SOLPS simulations as well as divertor Thomson scattering data. Furthermore, a new 2D parameterization of the outer divertor volume, which is required for the dynamic model, was developed. Due to its fast and local ne and Te profile measurements, the diagnostic is suitable for investigating fast processes such as divertor transitions and filaments.

Hormann, S., Cavedon, M., Griener, M., Wendler, D., Dux, R., Schmid, K., et al. (2024). Thermal helium beam diagnostic for 2D profile measurements in the divertor of ASDEX Upgrade. REVIEW OF SCIENTIFIC INSTRUMENTS, 95(11) [10.1063/5.0237317].

Thermal helium beam diagnostic for 2D profile measurements in the divertor of ASDEX Upgrade

Cavedon M.;
2024

Abstract

A new thermal helium beam diagnostic has been implemented in the outer lower divertor of the ASDEX Upgrade tokamak. The purpose of this diagnostic is to measure two-dimensional profiles of electron density (ne) and temperature (Te) with high temporal and spatial resolution. The geometry of the lines of sight is chosen to avoid the influence of prompt recycling and to optimize the resolution without significantly impacting the divertor structure. Moreover, the effect of long-term helium recycling has been analyzed, and its amplitude compared to the active signal is negligible. Finally, the reconstruction of ne and Te is done via a collisional radiative model, while a static and a dynamic model were implemented and compared with SOLPS simulations as well as divertor Thomson scattering data. Furthermore, a new 2D parameterization of the outer divertor volume, which is required for the dynamic model, was developed. Due to its fast and local ne and Te profile measurements, the diagnostic is suitable for investigating fast processes such as divertor transitions and filaments.
Articolo in rivista - Articolo scientifico
Electric diverters; Electron density measurement; Hadrons; Magnetoplasma; Positive ions; Superfluid helium; Tellurium compounds; Tokamak devices
English
13-nov-2024
2024
95
11
113507
none
Hormann, S., Cavedon, M., Griener, M., Wendler, D., Dux, R., Schmid, K., et al. (2024). Thermal helium beam diagnostic for 2D profile measurements in the divertor of ASDEX Upgrade. REVIEW OF SCIENTIFIC INSTRUMENTS, 95(11) [10.1063/5.0237317].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/537222
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