Speaker
Description
The EPOS stellarator, a compact device for confining electron-positron plasmas, will leverage high-temperature superconductors (HTS) to generate a highly optimized toroidal magnetic field. To achieve this, we will employ non-planar, non-insulated coils made from rare-earth barium copper oxide (ReBCO) tapes, which enable a 2T magnetic field on axis and a plasma volume of approximately 10L. We will use a closed-cycle helium compressor system, which provides cooling of the HTS coils to 20K and superconducting leads to supply current.
In this contribution, we present the engineering design of EPOS, including the optimized winding pack orientation to mitigate torsion and bending-induced damage to the brittle, ceramic ReBCO tape, as well as the mechanical analysis of Lorentz forces on the support structure.
Additionally, we present the thermal and electrical system design, which is critical for achieving the low power consumption required by the cryocooler. To minimize heat loads and ensure reliable operation, we have optimized the thermal and electrical interfaces to achieve very low contact resistances between the superconducting leads and the 22 coils as well as to deliver sufficient cooling power to their winding packs.
We discuss the techniques we employ for manufacturing the non-planar coils, including the development of a winding machine to ensure high-quality and reliable coil production.
Our design decisions were informed by a comprehensive hardware test campaign, which involved the successful construction and testing of a non-planar coil with optimized winding pack orientation, supported by a 3D printed aluminium structure. Notably, we achieved a peak field of 3T on the superconductor, which resembles the conditions in the EPOS experiment.
