A phenomenon in which a superconductor suddenly loses its superconducting properties. Quench can have a number of causes, such as a rise in temperature or magnetic field inside the superconductor. As soon as the superconductor returns to its normal, resistive state, the energy stored in it begins to be converted into heat. The place where the quench started heats up neighbouring areas, which also lose superconductivity. The superconductor is then in danger of overheating, even melting and destruction. An impending or developing quench can be detected by sensors, so the thermal energy can be extracted from the superconductor before it causes damage. Therefore, superconducting magnets also contain a copper winding that allows the excess energy to be quickly dissipated during the eventual quench.