In-situ calibration of charge exchange spectroscopy for spatially resolved measurements of helium-hydrogen density ratio in Wendelstein 7-X
Abstract In-situ calibration of charge exchange spectroscopy for spatially resolved measurements of helium-hydrogen density ratio is described in this paper. The helium-hydrogen density ratio in the core plasma is derived from the intensity ratio of the active helium line HeII (468.6 nm) and hydrogen line HI (656.3 nm) due to the charge exchange recombination process between fully ionized ions and neutral beam. This system is calibrated by the helium-hydrogen density ratio evaluated from HeII (656.0 nm) and HI (656.3 nm) in the recombining phase at the end of the discharge. The helium-hydrogen density ratio at the plasma center derived from the calibrated charge exchange spectroscopy is compared with the influx ratio estimated from the passive spectroscopy.
Authors
- K. Rahbarnia (ORCID: https://orcid.org/0000-0002-5550-1801)
- M. Zilker
- P. Zs. Pölöskei (ORCID: https://orcid.org/0000-0001-7781-5599)
- U. Neuner (ORCID: https://orcid.org/0000-0002-4293-0148)
- O. Ford (ORCID: https://orcid.org/0000-0002-5646-4758)
- J. Baldzuhn (ORCID: https://orcid.org/0000-0001-5667-351X)
- M. Yoshinuma (ORCID: https://orcid.org/0000-0002-5113-9710)
- Thilo Romba (ORCID: https://orcid.org/0000-0002-2727-9385)
- K. Ida (ORCID: https://orcid.org/0000-0002-0585-4561)
- H. Thomsen (ORCID: https://orcid.org/0000-0002-6835-1494)
- M. Zanini (ORCID: https://orcid.org/0000-0002-8717-1106)
Institutions
- National Institutes of Natural Sciences (JP)
- National Institute for Fusion Science (JP)
- Max Planck Institute for Plasma Physics - Greifswald (DE)
Publication Details
- Journal
- Journal of Instrumentation
- Published
- 2025-07-01
- DOI
- https://doi.org/10.1088/1748-0221/20/07/p07006
- Primary Topic
- Quantum, superfluid, helium dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00