Plasma-Wall Interaction Experts met in Jülich
The interaction of a fusion plasma with the surrounding walls is a key issue on the way towards a fusion power plant. The subject, increasingly in the focus of European fusion research, is of utmost importance for ITER. Experts in the field of plasma-wall interaction met at Research Centre Jülich (FZJ, Germany) on October 14-15, 2004 to discuss the current progress and to work out immediate future plans within the EU Task Force on Plasma-Wall Interaction. The Task Force was started two years ago under the leadership of Dr. V. Philipps from FZJ with J. Roth (IPP Garching) and A. Loarte (EFDA) as deputy leaders, who will remain in function until the end of 2005.
The participants (see photograph - Dr. Elżbieta Fortuna 11th from the right) have analysed in detail recent reports of the six special working groups on chemical erosion, gas balance, transient heat loads, high-Z plasma facing components, tritium removal, and dedicated technology tasks. To highlight some of the results, progress has been achieved in qualifying the carbon chemical erosion source under the divertor conditions in ITER, indicating lower carbon influx than previously assumed. Also the temporal and spatial distribution of disruption power loads indicate less critical margins than previously assumed. However, the main critical question associated with the present ITER wall material choice remains the long term tritium inventory. More work is necessary in present fusion devices to qualify tritium removal methods which are applicable in ITER. Interesting progress with the use of tungsten as main chamber wall material has been obtained in ASDEX Upgrade.
The Task Force is largely organised along topics which is seen as a key ingredient to achieve progress. In the topical areas, well-defined questions and areas in which efforts will be concentrated in the coming year have been identified.
The reports of the special expert working groups were followed by presentations of the work performed in thirteen European Fusion
Associations, for the first time including Poland and Slovenia. All questions picked out during the workshop have been discussed in view of their relevance to ITER.