Rearrangement of Superconducting Wires in Solenoidal Magnets

The strain behavior of the superconducting solenoidal coil form has a close relationship with the training behavior of the quench current. This relationship can not be explained by means of models of wire motion, friction and resin cracking, which are known as mechanical disturbances, as the cause of quench. Therefore, a wire rearrangement model was proposed, where the accumulation of the microscopic displacements of the multiple turns of superconducting wire manifests itself in the strain behavior of the form. Based on this model, the strain energy of superconducting wire released by rearranging the turns was investigated theoretically and experimentally. As a result it was confirmed that the released energy exceeds the minimum quench energy, MQE, resulting in the instability of a sample coil. From this result, it is expected that the wire rearrangement model is useful for estimating the stability.