CTS Asdex Upgrade

Asdex Upgrade is a medium-sized tokamak located in Germany north of Munich. Asdex Upgrade is equipped with powerful fast-ion heating systems, with the neutral beam injector (NBI) as the main fast-ion source. Studies of fast-ion interaction with the plasma are crucial for harvesting fusion energy in future tokamaks. The fast ions created in the fusion processes need to heat the plasma without exciting plasma instabilities. In the section for Plasma Physics and Fusion Energy, we have installed two fast-ion diagnostics at Asdex Upgrade which measure the fast-ion distribution function by means of collective Thomson scattering (CTS). These microwave diagnostics are based on principles that were pioneered by the group at the Textor tokamak, where time resolved measurements of the fast-ion distribution function have illuminated the interaction between the fast ions and plasma instabilities from a new angle.

The CTS equipment at Asdex Upgrade is also used to develop a measurement technique which resolves the plasma composition in the centre of the plasma. Such a technique will have a major impact on the fusion yield control in future power plants and in the test reactor ITER.  

 Asdex Upgrade with plasma Asdex Upgrade without plasma 
Asdex Upgrade with plasma    Asdex Upgrade without plasma




Stefan Kragh Nielsen
Senior Scientist
DTU Physics
+45 46 77 45 34