Illustration: ITER

Danish measuring equipment to measure 200 million degrees plasma

Physics Energy
DTU researchers have concluded the biggest Danish contract to date with ITER, the world's first major experimental fusion power plant.

Danish equipment will measure fusion plasma at temperatures of up to 200 million degrees in the ITER experiment, which is the world's largest fusion experiment. ITER is presently under construction in the south of France. Here work is underway to generate energy by fusing atomic nuclei. DTU has just been awarded the task of designing the measuring equipment. This is the biggest Danish order to date from Fusion for Energy (F4E), the agency responsible for European deliveries to ITER.

The contract will run for the next four years and takes the form of a framework agreement between F4E and a consortium comprising DTU and the Portuguese Instituto Superior Technico (IST) in Lisbon.

The measuring equipment, the so-called CTS system (Collective Thomson Scattering), will monitor the fast ion particles in fusion plasma at ITER, which is scheduled for completion in 2020. The system has been developed in the Plasma Physics and Fusion Energy Section at DTU Physics, which is at the international forefront of development and operation of CTS systems.

Challenging technique
“For the first time ever, ITER will make it possible for us to study the behaviour of a fully operational fusion plasma. The CTS diagnostic is crucial for understanding the dynamics of ions in the plasma,” says Søren Bang Korsholm, Senior Scientist at DTU Physics and head of the project.

The measuring system will provide information about how fast ions from the fusion process behave, and how the balance between deuterium and tritium in the plasma affects the fusion efficiency.

The system will contain a microwave source—a so-called gyrotron—which sends an electromagnetic wave beam with a power of 1 MW and a frequency of 60 GHz into the plasma. The electromagnetic waves interact with the electron density perturbations and are scattered in different directions with a given frequency shift.

A number of mirrors and horns outside the plasma capture part of the scattered electromagnetic waves, and the received spectrum of the signal makes it possible to establish the movement and distribution of the ions in the plasma—especially the fast ions from fusion processes.

Read more about Fusion for Energy (F4E)
Read more about ITER