New issue of ASDEX Upgrade Newsletter
Information on research with the ASDEX Upgrade fusion device
ASDEX Upgrade Letter deals with present developments and research results from the ASDEX Upgrade tokamak fusion device at Garching, on which scientists from all over Europe are working.
Issue 21/2019 deals with the preparation of ITER operation. ASDEX Upgrade was used to experiment with plasmas made of hydrogen and helium, the working gases for ITER’s start of operation. In order to test whether such plasmas can achieve the desired High-confinement regime in ITER, the transition from the Low to the High-confinement regime was investigated at ASDEX Upgrade for various gases. These experiments complement earlier work on JET and demonstrate the efficiency of the European step ladder approach from ASDEX Upgrade via JET to ITER – devices of different size but similar geometry.
Special instabilities localised at the edge of the plasma (ELMs) are not a problem for today’s medium-sized fusion facilities. In ITER, however, they have to be greatly reduced; in a later demonstration power plant they are hardly acceptable. As it turns out, fusion plasma physics can still surprise: The Letter reports on a previously unknown path to a stationary ELM-free plasma, which was discovered rather “accidentally”.
Finally, a fundamental problem, the turbulent transport of energy and particles, has been addressed for the first time in a direct similarity experiment betrween the ASDEX Upgrade tokamak and the Wendelstein 7-X stellarator in Greifswald – with promising results.