Stability considerations of multifilamentary MgB2 tape
Supercond. Sci. Technol,. 19 (2006), 184–189
Stenvall1, AKorpela1, RMikkonen1 and G Grasso2
1 Institute of Electromagnetics, Tampere University of Technology, PO Box 692,
33101 Tampere, Finland
2 Columbus Superconductors srl, c.so F.M. Perrone 24, 16152 Genova, Italy
The risk of overheating arises if the stability of an MgB2 coil is lost. This is mainly due to the low thermal conductivity of the matrix metal, which is typically iron or nickel. Due to a strong chemical reaction, copper can be used in contact with MgB2 only in specific cases: in situ preparation route and low formation temperature. However, recent developments in the manufacture of MgB2 conductors have resulted in stabilized MgB2 tapes. In any case, the stability considerations of MgB2 conductors are of great importance. We studied computationally the stability of an MgB2/Ni/Fe/Cu tape manufactured by Columbus Superconductors. First, the effective material properties of the tape were computed. Based on these material properties, we computed the basic quench characteristics (minimum propagation zone, minimum quench energy and normal zone propagation velocities) for the tape at 15, 20 and 25 K. The tape unit cell model was used in computations. The computed stability results were compared with the measured ones of a monofilament MgB2/Cu/Ni tape and commercial LTS and HTS. According to the results, the basic quench characteristics computed fit between the ones of LTS and HTS materials.