In January 2011, the first plasma lit up in the plasma wall interaction (pwi) experiment psi-2 at forschungszentrum Jülich.

he seven metre long and three ton heavy linear machine produces a cylinder- shaped plasma which features reactor-like heat and particle fluxes. In the new device, samples of wall materials are exposed to plasma conditions which will be relevant to subsequent power stations. The plasma, as well as the sample surface, is analysed before, during and after this exposure. Linear plasma devices are well suited for PWI studies, because they can be operated in steady state and their set-up is less complex than that of tokamaks. They also enable more accurate measurements of the plasma and the wall surface. In order to also investigate neu tron-activated or toxic wall materials, a second, similar experiment called
JULE-PSI will be installed inside Jülich’s Hot Cells. It is expected to start operating in 2015.

The powerful plasma of a fusion power plant erodes the surface of the reactor wall and the resulting debris can reduce the plasma performance. Plasma Wall Interaction studies investigate these effects under reactor-like conditions: Highly energetic tritium-deuterium plasmas operated in long pulses or steady state.

Unique centre of competences

JULE-PSI at For schungs zentrum Jülich is one of several linear devices for Plasma Wall Interaction studies under construction or planning in Europe. VISION I at the Bel gian Nuclear Research Centre SCKCEN also started in January 2011 and will operate with tritium plasmas at moderate power as of 2012. MAGNUMPSI at the FOM In sti tute for Plasma Physics in The Nether – lands began its pilot phase in spring 2009. It features extremely high particle and heat fluxes and densities thus simulating conditions even for wall areas that are in touch with the plasma, such as the divertor (see Fusion News May 2009). All three institutions pool their resources in the Trilateral Euregio Cluster (TEC), forming a unique worldwide centre of competence for Plasma Wall Interaction studies addressing the needs of post- ITER installations.