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P: Fachverband Plasmaphysik
P 21: Magnetic Confinement II
P 21.1: Hauptvortrag
Donnerstag, 3. März 2016, 11:00–11:30, b302
The behavior of helium in fusion plasmas — •Athina Kappatou1, Rachael M. McDermott1, Clemente Angioni1, Thomas Pütterich1, Ralph Dux1, Michael G. Dunne1, Rudolf Neu1, Alexander Lebschy1,2, Eleonora Viezzer1, Marco Cavedon1,2, the EUROfusion MST1 Team3, and the ASDEX Upgrade Team1 — 1Max-Planck-Institut für Plasmaphysik, Garching, Germany — 2Physik-Department E28, TU München, Garching, Germany — 3See http://www.euro-fusionscipub.org/mst1
The presence of helium is fundamentally connected to the performance of a fusion reactor. The energetic α-particles produced by the D-T fusion reactions will heat the plasma through collisions. However, the thermalised helium content in the plasma core should be minimized as it dilutes the fusion fuel. Hence, understanding the transport of helium is indispensable, as is the availability of experimentally validated theoretical tools, to predict the helium density profile in future machines.
Helium transport investigations have been undertaken in dedicated experiments at ASDEX Upgrade. The experimental helium density profiles, measured with charge exchange spectroscopy, are compared with the theoretical predictions, obtained from gyrokinetic simulations. The comparison revealed features, which indicate a missing piece in the current understanding of low-Z impurity transport. In addition, while it is well known that the confinement in helium plasmas is lower than in deuterium plasmas, recent experiments show that helium deteriorates plasma confinement even at low concentrations. The efforts to shed light on the physics behind this detrimental effect will be presented.