Design, Manufacture and Characterization of High Temperature Superconducting D-Shaped Coil

Nowadays, high temperature superconductors have been proposed for high current density at high magnetic field applications such as tokamak and MRI machines. In this paper, dependency of critical current on magnetic field, temperature and different curvature radius for specific sample of Bi-2223/AgMg composite tape are obtained. By using this superconducting tape, a D-shaped pancake coil is designed and built. The coil characteristics in the liquid nitrogen temperature are reported and compared with the results of the tape. Furthermore, we have obtained the portion effects of the bending and self-field in the critical current drop. Hysteresis behavior as a function of current rate during ramp up and ramp down cases on the voltage current curve at liquid nitrogen temperature has been investigated. Then by considering equivalent circuit for high temperature superconducting magnet, the behavior of the voltage in terms of current is analyzed. Maximum field generated in this magnet is obtained and quench minimum energy is measured for working current of 37 A at nitrogen vapor.