Inhibited cavitation in lanthanum-doped tungsten under multiple melt exposures in GLADIS and ASDEX Upgrade

• DOI: 10.1088/1741-4326/adbb7d
• Publication Date: 2025-02-28T22:49:32Z
• Authors: Yue Yuan; Ying Qin; Karl Krieger; Henri Greuner; Bernd Böswirth; Hanqing Wang; Mengchong Ren; Long Cheng; Guang-Hong Lu
• Keywords: ASDEX Upgrade; Lanthanum

Abstract Melt ejection and melt motion of tungsten (W) as a plasma-facing material due to accidental thermal overload events are primary concerns for ITER DEMO. Previous experiments have revealed that W-1wt.% La₂O₃ is an effective suppressing cavitation under single pulsed heat load [1]. To further investigate this effect, both W (WL10) were subjected multiple exposures in the high flux facility GLADIS tokamak ASDEX Upgrade (AUG). In GLADIS, H/He high-power neutral particle beams used, with total energy density 41-50 MJ/m² per pulse, adjusted by pulse duration. AUG, eight ELMing H-mode deuterium (D) plasma discharges (#37680-87) employed samples exposed divertor manipulator DIM-II. The results surface cross-sectional morphologies resolidified layers similar AUG. pure exhibited pronounced cavitation, numerous spherical voids layer. contrast, WL10 developed undulating morphology dense layer at top, free lanthanum particles, indicating sustained suppression even after had vaporized from top during previous melting. This effect likely primarily formation surface, which exposes still La₂O₃-rich deeper regions. particles participated subsequent melting cycles, continuously preventing cavitation. Additionally, we compared D retention was significantly reduced 2.5×10²¹ 4.4×10¹⁹ D/m² slightly decreased 1.5×10²¹ 1.2×10²¹ when comparing unmolten molten samples. Overall, AUG confirm W-La₂O₃ good cavitation-resistant material, effectively melt.