Experimental study of solenoid using Bi2223/Ag tape with ferromagnetic disks

We have studied a disk-set solenoid: a superconducting solenoid that uses Bi2223/Ag tape and has ferromagnetic disks set on both its ends. A magnetic field applied to the tape conductors at the edges turns so it is parallel to the tape surface. We manufactured a solenoid made of 10 double pancakes and investigated differences in its characteristics with and without the ferromagnetic disks. The results showed that setting the disks increased the critical current of a double pancake on the edge 1.3 times. And measurements using the Hall elements demonstrated that the magnetic field applied perpendicularly to the tape surface near the edge was reduced to the same degree as indicated by the numerical calculation.