After modification of the ASDEX Upgrade divertor, i.e., installation of the
'LYRA'-divertor, extensive helium exhaust and transport studies have been
performed to investigate two different aspects important for the developmen
t of a steady-state fusion device: (1) helium transport in the scrape-off l
ayer (SOL) and divertor with a divertor geometry similar to the one foresee
n for ITER, and (2) helium transport in the plasma core with internal trans
port barriers (ITBs). In ohmic and H-mode discharges larger compression rat
ios and enrichment factors as competed to divertor I have been found. With
the new divertor configuration both quantities depend on the heating power
and deteriorate with divertor detachment. In ITB-discharges with an I-I-mod
e edge, helium exhaust is rather slow - as expected for such low density sc
enarios - but not hindered by the transport barrier. (C) 2001 Elsevier Scie
nce B.V. All rights reserved.