Superconducting magnet

A magnet whose windings use superconductors to carry current with negligible electrical resistance below a critical temperature. It can generate strong magnetic fields with low resistive power loss, but requires cryogenic cooling and protection against quenching.

Superconductivity: A state in which certain materials exhibit zero electrical resistance and expel magnetic fields below characteristic conditions. Its zero-resistance state lets a closed magnet winding sustain current with little electrical loss.
Superconducting wire: A conductor engineered to carry current in its superconducting state, often as a composite wire or tape. The wire’s current capacity and mechanical support constrain magnet performance.
Magnetic resonance imaging: A medical imaging technique that uses nuclear magnetic resonance to create detailed images of the body. Clinical MRI scanners commonly rely on persistent-field superconducting magnets.
Resistive electromagnet: An electromagnet whose current flows through ordinary resistive conductors. It avoids cryogenic cooling but wastes more electrical power as heat at high fields.
Magnetic pressure: The mechanical stress associated with a magnetic field, proportional to the field-energy density. Strong fields exert forces that the coil and support structure must withstand.
Critical temperature: The temperature below which a material undergoes a phase transition into a distinct state. A superconducting winding must remain below its material’s transition temperature.
Niobium–titanium: A ductile superconducting alloy widely used in low-temperature magnets. Its workability and mature fabrication make it common in accelerator and MRI coils.
Nuclear magnetic resonance spectroscopy: A technique that uses nuclear spin responses in a magnetic field to determine molecular structure. Strong, stable superconducting fields improve spectral resolution and sensitivity.
Permanent magnet: A material that produces a persistent magnetic field without an external electric current. It needs no powered coil or cryostat, but offers less field adjustability and strength.
Quench protection: Methods for detecting and safely managing a superconducting magnet’s transition to a resistive state. Protection circuits limit local heating and redirect energy during a quench.

Linked from 21 pages