Prediction of the quench current of a large magnet with a small model test

The quench current of any large nonsteadily stabilized magnet under design can be predicted by the testing of a relatively small model. The model should reproduce the main features of the design and the manufacturing technique as well as the temperature margin and the amplitude of thermo-mechanical excitations inherent in the magnet being designed and dependent on the stress level. Usually it is unfeasible to reach a high stress level in a small model. However, it is possible when external forces are used. An experiment with a superconducting force generator is described here. It has allowed the testing of two different models of a 50 MJ coil under high compressive load, to choose the best and to determine the necessary temperature margin for the large coil.