Reprint of: Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

V. Rohde, M. Balden
2017 Nuclear Materials and Energy  
INTRODUCTION: In the stand ard picture of plasm a w all interaction , arcs are not taken into account as erosion source: in the 80 th it w as show n that for carbon physical and chem ical sputtering d om inate and arcs are only triggered d uring unstable plasm a phases w ith enhan ced MH D activity [1]. On the other hand arc traces are observed in all present fusion d evices. Due to the transition to m etal plasm a facing com ponents (PFCs) the role of arcing on erosion has to be reconsid ered
more » ... o be reconsid ered again. Recent investigations in ASDEX Upgrad e (AUG) show that ELMs m ay trigger arcs at som e locations [2] and the m orphology of a m ajor fraction of d ust collected can be explained by d roplet prod uction in arcs [3]. Whereas previous investigations use the typical AUG PFCs, i.e. tungsten (W) coating of 5 m icron thickness on a carbon substrate [4], bulk m aterial w as investigated this tim e. Tw o d ifferent m aterials w ere selected : W as m aterial of the ITER d ivertor and P92, m artensitic-ferritic high tem perature steel sim ilar to EUROFER, is the latter being und er d iscussion for DEMO. Arcing: In fusion d evices uni-polar arcs betw een plasm a and PFCs, orientated close to m agnetic field d irection, can be triggered if the voltage is in the ord er of 10 -30 V, d epend ing on the
doi:10.1016/j.nme.2017.09.004 fatcat:sslp6eduafbzvepkr3jg2vxknq