Mechanical response induced by flux jump in a cylindrical superconductor

The flux jump in bulk superconductors is accompanied by a rapid change in temperature and magnetic field, which can induce change in electromagnetic bodyforce and thermal stress. It is well known that bulk superconductors are brittle and have low mechanical strength, and thus, large electromagnetic bodyforce and thermal stress can cause damage of the bulk superconductor. In this paper, an electromagnetic-thermal-mechanical multi-physics model is adopted to compute the mechanical response of a bulk superconductor during flux jump in an external magnetic field. The results indicate that the flux jump in the bulk superconductors can also lead to the jump of the average electromagnetic force, temperature, stress, and strain. Meanwhile, it can be found that the flux jump can occur more easily with a faster change in the magnetic field, a lower ambient temperature, and a large-size superconductor. The results also show that the peak value of thermal strain is much larger than the strain generated by electromagnetic bodyforce during the flux jump. In addition, the change in strain has the same trend as that of the temperature. Thus, the strain may also be used to monitor the flux jump.