Date post: | 27-Mar-2015 |
Category: |
Documents |
Upload: | kylie-daugherty |
View: | 218 times |
Download: | 0 times |
ITPA Avilla January 2008 © Matej Mayer
Surface modifications and blistering of tungsten
exposed in ASDEX Upgrade
M. Mayer, M. Balden, S. Lindig, J. Roth, R. Neu, ASDEX Upgrade team
Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching, Germany
ITPA Avilla January 2008 © Matej Mayer
Blister formation in W, laboratory studies
W. Wang et al., JNM 299 (2001) 124
Surface modifications observed after
bombardment of W by hydrogen
in laboratory studies
Blister formation
Polycrystalline tungsten samples
(Langmuir probes) exposed
in AUG outer divertor
in 2007 for 2620 s
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
Blister-like structures are observed
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
Do these structures contain voids?
FIB using 30 keV Ga
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
Protective carbon coating
for FIB
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
Blister-like structures filled
with material, no voids
These are no blisters
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
But:
ITPA Avilla January 2008 © Matej Mayer
Langmuir probes from outer divertor
A few blisters are observed
in this area of the sample
ITPA Avilla January 2008 © Matej Mayer
Summary
• Blister-like structures are observed, but they are solid and do not contain voids No blisters
• A few blisters are observed in some areas of the sample
• Surface modifications of W due to plasma exposure are small