Superconducting Magnet Quench Codes
Quench codes model the transition of a superconducting magnet to the normal state, predicting temperature, voltage, and the protection a coil needs.
What a quench is
A superconductor carries current with no resistance only below a critical temperature, field, and current. If a spot exceeds these limits, it becomes resistive and heats, which can spread the normal zone. This quench, if unmanaged, concentrates the magnet's stored energy in a small region and can destroy the coil.
The physics to capture
- Normal-zone propagation along and between conductors
- Heat generation and diffusion through the conductor and structure
- Current redistribution as resistance appears
- Voltage development across the coil and the energy-extraction response
Modeling approach
Quench codes couple thermal diffusion, the temperature- and field-dependent conductor properties, and the electrical circuit including any dump resistor. They may be zero-dimensional for scoping or fully three-dimensional for detailed design, and often couple to the coolant flow that carries heat away in a cable-in-conduit conductor.
Protection
The purpose is to design protection: detect the quench early and safely extract the stored energy before the hot spot overheats. Codes predict the detection time available and the peak temperature and voltage for a given protection scheme, setting requirements on detection thresholds and dump circuits.
High-field context
High-field magnets store large energy densities, raising the stakes of quench protection. Modern high-temperature superconductors tolerate higher temperatures but propagate a normal zone slowly, which makes early detection harder, a trade-off that quench modeling quantifies for a specific conductor and coil.
The Hyperion breeder relies on high-field magnets, with peak field near 16.84 T and about 8 T on axis, so quench analysis is integral to confirming the magnet system can be protected.