Abstract Details
Abstracts
Author: Julien Dominski
Requested Type: Consider for Invited
Submitted: 2025-03-01 07:29:44
Co-authors: P. Maget, P. Manas, J. Morales, T. Barbui, L.F. Delgado-Aparicio, M. O’Mullane, C.S. Chang, R. Hager, S. Ku, F. Parra, A. Scheinberg
Contact Info:
PPPL
100 Stellarator rd
Princeton, 08540
USA
Abstract Text:
The mitigation of divertor loads by light impurity seeding in ITER will impact the radial distribution of tungsten ions and induced radiative losses, as demonstrated by this work based on WEST experimental results [1]. Tungsten peaking is predicted using collisional-turbulent gyrokinetic simulations and validated by synthetic bolometry diagnostics. While light impurities reduce the neoclassical tungsten peaking on-axis, the overall peaking increases due to reduced turbulence screening off-axis. This finding is crucial for the plasma current ramp-up phase of ITER, where light impurity seeding is desirable for achieving low temperatures at plasma-facing components and minimizing tungsten sputtering. It emphasizes the need for early ECRH heating to maintain margins on the core power balance. These results were obtained from exascale simulations carried out with the XGC code modeling all species kinetically. A single ion of tungsten, Z=25, was considered in this ohmic plasma where the core electron temperature does not vary significantly. This model is now enhanced by calculating the charge states from ionization/recombination with ADAS rates and by grouping them in bundles in the XGC and FACIT codes. Radiations of the different charge states are calculated and compared to soft X-ray diagnostics. This framework enables the validation of a first-principle approach on present experiments in a tungsten environment that requires a deep understanding before the start of ITER operations.
[1] J. Dominski et al 2025 Nucl. Fusion 65 016003 https://www.doi.org/10.1088/1741-4326/ad8c63
Characterization: 1.0
Comments: