Abstract
A superconducting magnet, not fully stabilized, has instability that a normal zone, induced by a certain local disturbance, may lead to normal transition of the magent as a whole. Approximate evaluation of propagation of normal zones in superconducting wires is outlined and some remarks are made for anisotropic propagation in magnets. As a typical example, an analytical expression proposed by Wilson is presented and is compared with experimental results in bare and insulated wires. Basic ideas of magnet protection from mechanical and thermal damages in quench process are explained in two types of protection systems by an external resistor and “quenchback.” New aspects of magnet protection are also discussed in prospective applications of superconducting magnet.
