Cooling modes for superconducting magnets

The requirements to be met for a conductor design are enumerated in a way which shows how the choice of the cooling mode affects each parameter. These requirements include aspects concerning the coil protection, the mechanical behaviour and the thermal behaviour. The possible cooling modes are analyzed in distinguishing between the roles which are played by the fluid and by the geometry. A review of essential properties of helium in its different states is given. Heat exchange properties and implementation problems are successively considered. Some compromise solutions used in different projects are eventually analyzed for the purpose of presenting definite examples.