Cold Tests of the Superconducting Coils for the Stellarator W7-X

A new plasma fusion experiment, Wendelstein 7-X (W7-X), is built in the Max-Planck Institute for Plasma Physics in Greifswald (IPP), Germany. This experiment employs superconducting coils, allowing for plasma discharges up to 30 minutes duration. W7-X will be an “optimized” stellarator with respect to plasma transport and stability. The W7-X magnet consists of 70 individual coils in a toroidal arrangement. Each coil of W7-X is thoroughly tested before installation in a cryogenic test facility at the Commissariat a l'Energie Atomique (CEA) in Saclay, France. The tests are essential, because no access is foreseen to the magnetic system during the entire operation period of W7-X. The test procedure will be described briefly, and some test results will be presented.