ERO and PIC simulations of gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade. (August 2017)

• Record Type: Journal Article
• Authors: Hakola, A.; Airila, M.I.; Mellet, N.; Groth, M.; Karhunen, J.; Kurki-Suonio, T.; Makkonen, T.; Sillanpää, H.; Meisl, G.; Oberkofler, M.
• Is Part Of: Nuclear materials and energy. Volume 12(2017)
• Page Start: 423
• Page End: 428
• Publication Date: 2017-08
• Subjects: ASDEX Upgrade -- Tungsten erosion -- ERO modelling -- PIC simulations -- Particle drifts -- Cross-field diffusion; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2016.09.012
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Net and gross erosion of W modelled by ERO and PIC simulations in ASDEX Upgrade. Erosion peak at the strike point induced by light impurities in the plasma. Noticeable deposition regions due to theE × B drift and small cross-field diffusion. Simulated net/gross erosion ratio 0.2–0.6 in line with literature data. Experimental estimate of 0.6–0.7 explained by multiple erosion-deposition cycles. Abstract: We have modelled net and gross erosion of W in low-densityl -mode plasmas in the low-field side strike point region of ASDEX Upgrade by ERO and Particle-in-Cell (PIC) simulations. The observed net-erosion peak at the strike point was mainly due to the light impurities present in the plasma while the noticeable net-deposition regions surrounding the erosion maximum could be attributed to the strongE ×B drift and the magnetic field bringing eroded particles from a distance of several meters towards the private flux region. Our results also imply that the role of cross-field diffusion is very small in the studied plasmas. The simulations indicate net/gross erosion ratio of 0.2–0.6, which is in line with the literature data and what was determined spectroscopically. The deviations from the estimates extracted from post-exposure ion-beam-analysis data (∼0.6–0.7) are most likely due to the measured re-deposition patterns showing the outcomes of multiple erosion-deposition cycles.