Effects of impregnating material failure on stability of superconducting magnet analyzed by wire dynamics simulation

The wire dynamics simulation has been performed to evaluate the stability o f the impregnated superconducting magnet. The relationship between quench c urrent and the impregnating material failure in the superconducting magnet was studied. In the impregnated superconducting magnet it is considered tha t the heating is induced by the cracking of the impregnating material or by the friction between mire and mire or mire and bobbin after the cracking. The wire dynamics simulation developed in this study can clarify the behavi or of a superconducting coil by solving the equation of motion for each mir e with time. In this simulation impregnating material was simulated as spri ngs which connect between wires. The stresses to the springs were calculate d, and mere used to decide the failure of the impregnating material. It was found that just after the impregnating material cracking the heating incre ased suddenly at the place where the cracking of the impregnating material was induced and results in quench. The sudden increase of heating was cause d by friction between mire and bobbin. This result suggests that the impreg nating material failure is closely related to the stability of superconduct ing magnet.