Development of 2T‐Class MgB2 Solenoid Coil

This paper reports on the fabrication and testing of a MgB2 coil made using a wind & react method. We made a 130m‐long Fe/Cu‐composite sheathed, SiC‐doped MgB2‐superconducting round wire using an in‐situ PIT method. Using a 92m‐long wire, we fabricated a solenoid coil with 722 turns. In the coil test, we measured the Ic of the coil under various external fields and temperatures. The Ic of the coil reached 162 A (Je = 340 A/mm2) at 4.2 K and in the external field of 2 T. The coil generated 2.2 T (the center magnetic field, Bo); thus the total field reached 4.2 T. The Je exceeded 100 A/mm2 in the external fields of 4 T, 2.5 T, and 1 T at 15 K, 20 K, and 25 K, respectively. The Jc of the coil was almost equal to that of the short sample. This indicates that the 92m‐long wire has a very homogeneous Jc distribution.