TY - JOUR
T1 - Laboratory investigations of arcing on W-coated graphite components
AU - Laux, M.
AU - Siemroth, P.
AU - Marx, M.
AU - Neu, R.
AU - Rohde, V.
AU - Balden, M.
AU - Endstrasser, N.
PY - 2013
Y1 - 2013
N2 - Results of laboratory experiments of arcing on graphite tiles coated by a W-layer are reported. The samples have been taken from coated tiles manufactured for ASDEX Upgrade (AUG). The motion of the arcs was observed by high-speed cameras. Additionally, sample plates have been exposed to collect macro-particles emitted by the arc. The eroded surfaces of the cathodes were investigated after experiment to characterize surface changes, tracks, and re-deposited particles. On the cathode strongly radiating immobile spots are observed by the cameras acting as sources of numerous macro-particles. At the surface large holes (diameter 17 μm) are found that perforate the W-layer and extend into the graphite bulk. Subsequent arcs tend to locate at the pre-existing holes. Hence, locally the W-coating is quickly and effectively broken, the W erosion is enhanced as compared to bulk W, and carbon is locally liberated despite the existence of an undamaged W-coating outside the arcing region.
AB - Results of laboratory experiments of arcing on graphite tiles coated by a W-layer are reported. The samples have been taken from coated tiles manufactured for ASDEX Upgrade (AUG). The motion of the arcs was observed by high-speed cameras. Additionally, sample plates have been exposed to collect macro-particles emitted by the arc. The eroded surfaces of the cathodes were investigated after experiment to characterize surface changes, tracks, and re-deposited particles. On the cathode strongly radiating immobile spots are observed by the cameras acting as sources of numerous macro-particles. At the surface large holes (diameter 17 μm) are found that perforate the W-layer and extend into the graphite bulk. Subsequent arcs tend to locate at the pre-existing holes. Hence, locally the W-coating is quickly and effectively broken, the W erosion is enhanced as compared to bulk W, and carbon is locally liberated despite the existence of an undamaged W-coating outside the arcing region.
UR - http://www.scopus.com/inward/record.url?scp=84885468993&partnerID=8YFLogxK
U2 - 10.1016/j.jnucmat.2013.01.162
DO - 10.1016/j.jnucmat.2013.01.162
M3 - Article
AN - SCOPUS:84885468993
SN - 0022-3115
VL - 438
SP - S758-S761
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
IS - SUPPL
ER -