Investigation of Bi-HTS wires for high field insert coils

In the High Magnetic Field Laboratory of the Institute for Technical Physics, the test facility HOMER II is currently under construction. In a first step, a magnetic field of 20 T in a bore of 180 mm produced by advanced LTS materials is aspired. In a second step, insert coils built of HTS wires are planned to be added in order to obtain resulting fields up to 25 T. With these intentions in the background, the superconducting properties of different Bi-HTS wires were investigated in a bath cooled superconducting magnet system at 4.2 K and magnetic fields up to 10 T. The critical current I_c was examined resistively using a high resolution four-point measurement technique. In consideration of the determined current carrying capacity of the wires, two layouts for HTS insert coils are presented